细胞培养用温度敏感凝胶的合成与性能研究

用丙烯酸（ARc）对壳聚糖（CS）进行化学改性，合成反应中问体壳聚糖衍生物CS-ARc，进一步合成不同配比的CS-ARc与N-异丙基丙烯酰胺（NIPA）的共聚凝胶P（CS-AAc-NIPA），通过红外光谱和元素分析等表征了产物的结构和组成，并研究了P（CS—ARc-NIPA）凝胶在水中和细胞培养基中的溶胀性能．结果表明共聚凝胶在水中和培养基中均显示较好的温度敏感性．对P（CS-ARc-NIPA）共聚凝胶进行细胞培养研究发现，其表面可成功种植成纤维细胞（L929），细胞贴附生长情况良好，表明材料具有很好的细胞相容性．当环境温度降低后，共聚凝胶发生疏水．亲水变化，导致其表面细胞自动脱附，从而避免了使用酶解法脱附细胞造成的细胞功能损伤．’     

蛋白质在水凝胶角膜接触镜上的吸附及对膜渗透性能的影响

以牛血清白蛋白(BSA)为模型蛋白,通过紫外分光光度法测定了BSA在共聚物水凝胶膜材料上的吸附量．研究了泪液中蛋白质在甲基丙烯酸-β-羟乙酯和N-乙烯基吡咯烷酮(HEMA—NVP)亲水性共聚物水凝胶的吸附情况．结果表明,蛋白质的吸附量随着吸附时间的增长而增大,4天基本达到吸附平衡．蛋白质在水凝胶上的吸附量随着水凝胶的平衡含水量增大而增大,吸附的蛋白质降低了水凝胶的离子通透性和透氧性．     

A novel vehicle for local protein delivery to the inner ear: injectable and biodegradable thermosensitive hydrogel loaded with PLGA nanoparticles

Delivery of biomacromolecular drugs into the inner ear is challenging, mainly because of their inherent instability as well as physiological and anatomical barriers. Therefore, protein-friendly, hydrogel-based delivery systems following local administration are being developed for inner ear therapy. Herein, biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) containing interferon α-2?b (IFN α-2?b) were loaded in chitosan/glycerophosphate (CS/GP)-based thermosensitive hydrogel for IFN delivery by intratympanic injection. The injectable hydrogel possessed a physiological pH and formed semi-solid gel at 37?°C, with good swelling and deswelling properties. The CS/GP hydrogel could slowly degrade as visualized by scanning electron microscopy (SEM). The presence of NPs in CS/GP gel largely influenced in vitro drug release. In the guinea pig cochlea, a 1.5- to 3-fold increase in the drug exposure time of NPs-CS/GP was found than those of the solution, NPs and IFN-loaded hydrogel. Most importantly, a prolonged residence time was attained without obvious histological changes in the inner ear. This biodegradable, injectable, and thermosensitive NPs-CS/GP system may allow longer delivery of protein drugs to the inner ear, thus may be a potential novel vehicle for inner ear therapy.     

Synthesis and characterization of carboxymethyl chitosan hydrogel: Application as site specific delivery for lercanidipine hydrochloride

In the present study, carboxymethylchitosan (CMCS) was prepared from chitosan, crosslinked with glutaraldehyde and evaluated in vitro as a potential carrier for site specific drug delivery of lercanidipine hydrochloride (LERH). LERH was incorporated at the time of crosslinking of CMCS. The chitosan was evaluated for its degree of deacetylation (DD) and average molecular weight, which were found to be 84·6% and 3·5 × 10⁴ Da, respectively. The degree of substitution on prepared CMCS was found to be 0·68. All hydrogel formulations showed more than 86% and 77% yield and drug loading, respectively. The swelling behaviour of prepared hydrogels were checked in different pH values, 1·2, 6·8 and 7·4, indicated pH responsive swelling characteristic with very less swelling at pH 1·2 and quick swelling at pH 6·8 followed by linear swelling at pH 7·4 with slight increase. In vitro release profile was carried out at the same conditions as in swelling and drug release was found to be dependent on swelling of hydrogels and showed biphasic release pattern with non-fickian diffusion kinetics at higher pH. The carboxymethylation of chitosan, entrapment of drug and its interaction in prepared hydrogels were checked by FTIR, ¹H-NMR, DSC and p-XRD studies, which confirmed formation of CMCS from chitosan and absence of any significant chemical change in LERH after being entrapped in crosslinked hydrogel formulations. The surface morphology of formulation S6 was checked before and after dissolution, revealed open channel like pores formation after dissolution.     

Microemulsion loaded hydrogel as a promising vehicle for dermal delivery of the antifungal sertaconazole: design,optimization and ex vivo evaluation

The purpose of the present study was to develop and optimize sertaconazole microemulsion-loaded hydrogel (STZ ME G) to enhance the dermal delivery and skin retention of the drug. Following screening of various oils for maximum drug solubility, 12 pseudoternary phase diagrams were constructed using oils (Peceol^®, Capryol^® 90), surfactants (Tween^® 80, Cremophor^® EL), a cosurfactant (Transcutol^® P) and water. A 2¹ × 3¹ × 2¹ × 3¹ full factorial design was employed to optimize a ME of desirable characteristics. The MEs were formulated by varying the oil type, oil concentration, surfactant type and surfactant: cosurfactant ratio. Optimized ME formulae F22 [5% Peceol^®, 55% Tween^® 80: Transcutol^® (1:2), 40% water] and F31 [5% Peceol^®, 55% Cremophor^® EL: Transcutol^® (1:2), 40% water] acquired mean droplet size of 75.21 and 8.68?nm, and zeta potential of 34.65 and 24.05?mV, respectively. Since F22 showed higher STZ skin retention during ex vivo studies (686.47?μg/cm²) than F31 (338.11?μg/cm²); hence it was incorporated in 0.5% Carbopol 934 gel to augment STZ skin retention capability. STZ ME G exhibited higher STZ skin retention (1086.1?μg/cm²) than the marketed product “Dermofix^® cream” (270.3?μg/cm²). The antimycotic activity against C.albicans revealed increased zones of inhibition for F22 and STZ ME G (35.75 and 30.5?mm, respectively) compared to Dermofix^® cream (26?mm). No histopathological changes were observed following topical application of STZ ME G on rats’ skin (n?=?9). Overall, the obtained results confirmed that the fabricated formulation could be a promising vehicle for the dermal delivery of STZ.     

Preparation and characterization of silk fibroin hydrogel as injectable implants for sustained release of Risperidone

The principal objective of the present study is to achieve a depot formulation of Risperidone by gelation of silk fibroin (SF). For this purpose, hydrochloric acid (HCl)/acetone-based and methanol-based hydrogels were prepared with different drug/polymer ratios (1:3, 1:6, and 1:15). For all the drug-loaded methanol-based hydrogels, gel transition of SF solutions occurred immediately and the gelation time was 1?min, while the gelation time of HCL/acetone-based hydrogels was around 360?min. According to the results obtined from Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) spectra, solvent systems and Risperidone could induce β-sheet structure, but HCL/acetone system had the lowest effect on induction of β-sheets. The crystallinity was increased by increasing the amount of Risperidone, and drug to polymer ratio of 1:3 possessed the highest crystallinity. Thermogravimetric analysis (TGA) indicated that increasing the amount of drug in formulation increased the stability of hydrogels, and methanol-based hydrogel with a ratio of 1:3 had the most stable structure. The release rate of Risperidone from methanol-based hydrogel at ratio of 1:3 was lower than that for HCl/acetone-based one, and it decreased by increasing the amount of Risperidone. The release of Risperidone from methanol hydrogel at ratios 1:3 and 1:6 continued up to 25?d which is acceptable for depot form of Risperidone and shows that the extended release of Risperidone was achieved successfully. In conclusion, SF hydrogel with the ability to respond to the environmental stimuli is an excellent candidate for injectable implants for extended release of Risperidone.     

基于酵母发酵致孔的小麦麸质蛋白/聚丙烯酸钠复合多孔水凝胶的合成及溶胀性能

以1-（3-二甲氨基丙基）-3-乙基碳二亚胺盐酸盐（EDC）活化丙烯酸（AA）羧基与小麦麸质蛋白（WG）接枝交联,酵母菌素分解WG中淀粉等多糖产生的CO₂作为孔模板,水溶液中自由基聚合制备了WG/聚丙烯酸钠（PNaA）多孔复合水凝胶（WG/PNaA）。FTIR分析表明,WG链上-OH、-NH₂等与AA成功接枝,并与中和的丙烯酸钠（NaA）在N,N'-亚甲基双丙烯酰胺（MBA）存在下聚合交联。场发射SEM（FESEM）证实,适量酵母菌素在WG体系中产生的CO₂可作为孔模板,在WG/PNaA网络中形成蜂窝状多孔结构,这种孔状结构不仅提高了WG/PNaA复合水凝胶在蒸馏水和生理盐水中的平衡溶胀倍率,也使其Schott's准二级动力学起始溶胀速率常数K_is提高至无酵母致孔样的5倍,Ritger半经验方程分析也证实其扩散系数n=0.5642,为non-Fickian溶胀,即孔状网络在凝胶溶胀初期有利于水分子快速扩散。考察了WG/PNaA复合水凝胶在蒸馏水-生理盐水、pH为2.2和7.4时磷酸缓冲溶液中的溶胀敏感性。结果表明,经过5次反复溶胀-去溶胀循环后仍具有良好的响应性,即多孔WG/PNaA复合凝胶同时具有灵敏可逆的盐和pH敏感性,为该水凝胶在药物控释领域应用提供了潜在可能。     

Evaluation of superabsorbent linseed-polysaccharides as a novel stimuli-responsive oral sustained release drug delivery system

Context: Advancement in technology has transformed the conventional dosage forms to intelligent drug delivery systems. Such systems are helpful for targeted and efficient drug delivery with minimum side effects. Drug release from these systems is governed and controlled by external stimuli (pH, enzymes, ions, glucose, etc.). Polymeric biomaterial having stimuli-responsive properties has opened a new area in drug delivery approach.

Objective: Potential of a polysaccharide (rhamnogalacturonan)-based hydrogel from Linseeds (Linum usitatissimum L.) was investigated as an intelligent drug delivery material.

Materials and methods: Different concentrations of Linseed hydrogel (LSH) were used to prepare caffeine and diacerein tablets and further investigated for pH and salt solution-responsive swelling, pH-dependent drug release, and release kinetics. Morphology of tablets was observed using SEM.

Results: LSH tablets exhibited dynamic swelling–deswelling behavior with tendency to swell at pH 7.4 and in deionized water while deswell at pH 1.2, in normal saline and ethanol. Consequently, pH controlled release of the drugs was observed from tablets with lower release (<10%) at pH 1.2 and higher release at pH 6.8 and 7.4. SEM showed elongated channels in swollen then freeze-dried tablets.

Discussion: The drug release was greatly influenced by the amount of LSH in the tablets. Drug release from LSH tablets was governed by the non-Fickian diffusion.

Conclusions: These finding indicates that LSH holds potential to be developed as sustained release material for tablet.     

Physicochemical characterization of diclofenac sodium-loaded poloxamer gel as a rectal delivery system with fast absorption

Rectal poloxamer gel systems composed of poloxamers and bioadhesive polymers were easy to administer to the anus and were mucoadhesive to the rectal tissues without leakage after the dose. However, a poloxamer gel containing diclofenac sodium could not be developed using bioadhesive polymers, since the drug was precipitated in this preparation. To develop a poloxamer gel using sodium chloride instead of bioadhesive polymers, the physicochemical properties such as gelation temperature, gel strength, and bioadhesive force of various formulations composed of diclofenac sodium, poloxamers, and sodium chloride were investigated. Furthermore, the pharmacokinetic study of diclofenac sodium delivered by the poloxamer gel was performed. Diclofenac sodium significantly increased the gelation temperature and weakened the gel strength and bioadhesive force, while sodium chloride did the opposite. The poloxamer gels with less than 1.0% sodium chloride, in which the drug was not precipitated, were inserted into the rectum without difficulty and leakage, and were retained in the rectum of rats for at least 6 hr. Furthermore, poloxamer gel gave significantly higher initial plasma concentrations and faster T_max of diclofenac sodium than did solid suppository, indicating that drug from poloxamer gel could be absorbed faster than that from the solid one in rats. Our results suggested that a rectal poloxamer gel system with sodium chloride and poloxamers was a more physically stable, convenient, and effective rectal dosage form for diclofenac sodium.     

Cadmium nanoclusters in a protein matrix: Synthesis,characterization, and application in targeted drug delivery and cellular imaging

Biotemplated metal nanoclusters have garnered much attention owing to their wide range of potential applications in biosensing, bioimaging, catalysis, and nanomedicine. Here, we report the synthesis of stable, biocompatible, water-soluble, and highly fluorescent bovine serum albumin-templated cadmium nanoclusters (Cd_NCs) through a facile one-pot green method. We covalently conjugated hyaluronic acid (HA) to the Cd_NCs to form a pH-responsive, tumortargeting theranostic nanocarrier with a sustained release profile for doxorubicin (DOX), a model anticancer drug. The nanocarrier showed a DOX encapsulation efficiency of about 75.6%. DOX release profiles revealed that 74% of DOX was released at pH 5.3, while less than 26% of DOX was released at pH 7.4 within the same 24-h period. The nanocarrier selectively recognized MCF-7 breast cancer cells expressing CD44, a cell surface receptor for HA, whereas no such recognition was observed with HA receptor-negative HEK293 cells. Biocompatibility of the nanocarrier was evaluated through cytotoxicity assays with HEK293 and MCF-7 cells. The nanocarrier exhibited very low to no cytotoxicity, whereas the DOX-loaded nanocarrier showed considerable cellular uptake and enhanced MCF-7 breast cancer cell-killing ability. We also confirmed the feasibility of using the highly fluorescent nanoconjugate for bioimaging of MCF-7 and HeLa cells. The superior targeted drug delivery efficacy, cellular imaging capability, and low cytotoxicity position this nanoconjugate as an exciting new nanoplatform with promising biomedical applications.

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Synthesis and characterization of thiolated carboxymethyl chitosan-graft-cyclodextrin nanoparticles as a drug delivery vehicle for albendazole

A new strategy for the synthesis of thiolated carboxymethyl chitosan-g-cyclodextrin nanoparticles by an ionic-gelation method is presented. The synthetic approach was based on the utilization of 1,6-hexamethylene diisocyanate during cyclodextrin grafting onto carboxymethyl chitosan. The use of the 1,6-hexamethylene diisocyanate resulted in reactions between cyclodextrin and active sites at the C₆-position of chitosan, and preserved amino groups of chitosan for subsequent reactions with thioglycolic acid, as the thiolating agent, and tripolyphosphate, as the gelling counterion. Various methods such as scanning electron microscopy, rheology and in vitro release studies were employed to exhibit significant features of the nanoparticles for mucosal albendazole delivery applications. It was found that the thiolated carboxymethyl chitosan-g-cyclodextrin nanoparticles prepared using an aqueous solution containing 1 wt% of tripolyphosphate and having 115.65 (μmol/g polymer) of grafted thiol groups show both the highest mucoadhesive properties and the highest albendazole entrapment efficiency. The latter was confirmed theoretically by calculating the enthalpy of mixing of albendazole in the above thiolated chitosan polymer.     

纳米SiO2增强聚乙烯醇缩乙醛凝胶的温敏性研究

以正硅酸乙酯(TEOS)前驱体,采用溶胶-凝胶法向部分缩醛的聚乙烯醇(APVA)水溶液中引入二氧化硅(SiC2)粒子,再通过冷冻/解冻法制备了温敏性聚乙烯醇缩乙醛(APVA)/二氧化硅(SiO2)复合凝胶.用扫描电镜、红外光谱和力学性能分析仪对产物的结构、微观形貌和力学性能进行了表征,并对其温敏性的影响因素进行了研究....     

Synthesis, characterization and transfection of a novel folate-targeted multipolymeric nanoparticles for gene delivery

Novel folate-conjugated biodegradable multipolymeric nanoparticles (NPs) were constructed and evaluated for potential use in gene delivery to human cervical carcinomas Hela cells, which overexpressed folate receptors. Folate-poly(ethylene glycol)-poly(d, l-lactic-co-glycolic acid) (PELGA-F) was synthesized and collaborated with poly-l-lysine (PLL) to form polymer-polycationic peptide-DNA (PPD) NPs. Fluorescein sodium and polylysine-condensed DNA (PD) were encapsulated in both PELGA nanoparticles (PELGA-NPs) and folate modified nanoparticles (PELGA-F-NPs), which were prepared by a modified solvent extraction/evaporation method. Effects of the folate conjugation and PLL introduction on the uptake of NPs was qualified by fluorescent invert microscopy and quantified by spectrofluorometric measurement, while effect on the gene expression was measured by X-gal staining and luciferase assay, both using Hela cells as an in vitro model. Results showed that cellular uptake of NPs was enhanced by folate modification, but had no difference after PLL encapsulation. In transfection tests, increased gene expression also confirmed the different functions of folate and PLL introduction. It is feasible that folate-linked multipolymeric NPs should be an efficient targeted carrier for gene delivery.     

炸药化学标记物DMNB的合成方法与标识特性

为应对公共安全领域爆炸恐怖袭击威胁,增加可塑性炸药的安检检出率,对炸药化学标记物DMNB的合成方法进行了实验研究,对一步法和二步法合成DMNB技术途径的原理和产出率等进行了对比。确定了相转移法氯代偶合二步合成DMNB为优选方案,并分别用GC-MS、FT-IR、FT-Raman表征DMNB的标识特性和结构。实验结果表明,DMNB在不同检测环境下具有易被现有检测分析仪器快速检出的明确标志性信息,具有明显的标识特性,可满足低挥发性炸药标记物的基本要求,且用氯代-偶合法合成DMNB,具有产出率高、纯度高和成本低的特点,有利于进一步开展DMNB作为低挥发性炸药标记物的实用化研究。     

炸药化学标记物DMNB的合成方法与标识特性

为应对公共安全领域爆炸恐怖袭击威胁,增加可塑性炸药的安检检出率,对炸药化学标记物DMNB的合成方法进行了实验研究,对一步法和二步法合成DMNB技术途径的原理和产出率等进行了对比。确定了相转移法氯代偶合二步合成DMNB为优选方案,并分别用GC-MS、FT-IR、FT-Raman表征DMNB的标识特性和结构。实验结果表明,DMNB在不同检测环境下具有易被现有检测分析仪器快速检出的明确标志性信息,具有明显的标识特性,可满足低挥发性炸药标记物的基本要求,且用氯代-偶合法合成DMNB,具有产出率高、纯度高和成本低的特点,有利于进一步开展DMNB作为低挥发性炸药标记物的实用化研究。     

Synthesis and characterization of a pH/temperature responsive glycine-mediated hydrogel for drug release

In this work, a pH/temperature responsive hydrogel (PMEA) from N-acryloylglycine methyl ester (NAGME), N-acryloylglycine ethyl ester (NAGEE), and acrylic acid (AAc) was synthesized by free radical polymerization. The swelling behaviors and drug release properties of hydrogels were systematically investigated at different temperature, pH, and AAc content. It was found that the hydrogel PMEA demonstrated pH and temperature responsive nature. The caffeine-release behaviors showed that only 49.1% caffeine was released from PMEA in pH 2.70 phosphate buffer solution (PBS) after 500 minutes, whereas more than 93.9% caffeine was gradually diffused into the medium in pH 7.49 PBS over the same time interval. In addition, the caffeine release was much higher at 37°C than that at 14°C in deionized water. As seen from the results, the PMEA seems to be a potential drug carrier with pH-temperature responsiveness.     

Albumin as a carrier for NO delivery: preparation,physicochemical characterization,and interaction with gold nanoparticles

Background: Nitric oxide (NO) is a gaseous transmitter playing numerous physiological roles and characterized by a short half-life. Its binding to endogenous thiols increases its stability, facilitating its storage and transport. The purpose of this study was to investigate the nitrosated serum albumin (SA-SNO) and to provide a reference for its easy preparation for further use in in vitro studies.

Methods: Serum albumin (SA) was S-nitrosated by reacting with (i) NaNO₂ in acidic medium; (ii) different low-molecular weight S-nitrosothiols (RSNO) (S-nitrosocysteine (CysNO), S-nitrosoglutathione (GSNO), and S,S'-dinitrosobucillamine (Buc(NO)₂)); and (iii) diethylamine NONOate (DEA/NO). SA-SNO was purified by size exclusion chromatography and the S-nitrosation site and the rate were studied by mass spectrometry and Griess–Saville assay, respectively. Then, SA-SNO was characterized by spectrofluorimetry, dynamic light scattering, and circular dichroism. Finally, SA-SNO reactivity with citrate stabilized gold nanoparticles (AuNP-citrate) was investigated via determination of NO release.

Results: S-nitrosation rates of SA were 90.1?±?3.3, 76.8?±?2.7, 80.3?±?3.2, 84.8?±?5.0, and 15.4?±?1.9% (n?=?5), when SA was reacted with acidified NaNO₂, CysNO, GSNO, Buc(NO)₂, and DEA/NO, respectively. The physicochemical characterization indicated that the resulting product corresponded to a mono-S-nitrosothiol (on cysteine-34), and the conformational construction remained unchanged. Stability studies showed that the NO content was preserved over 1 week. AuNP-citrate reacted with SA-SNO with increase of its hydrodynamic diameter but preservation of SNO bond.

Conclusions: SA-SNO prepared and stored under the reported conditions affords a well-defined reference suitable for in vitro studies.     

Development and physico-mechanical characterization of carrageenan and poloxamer-based lyophilized matrix as a potential buccal drug delivery system

Context and objectives: The buccal mucosa presents a unique surface for non-invasive drug delivery and also avoids first-pass metabolism. The objective of this study was the formulation development of polymeric mucoadhesive lyophilized wafers as a matrix for potential buccal drug delivery.

Materials and methods: Differential scanning calorimetry (DSC) was used to develop an optimum freeze-cycle, incorporating an annealing step. The wafers were prepared by lyophilization of gels containing three polymers, κ-carrageenan (CAR 911), poloxamer (P407) and polyethylene glycol 600 (PEG 600). The formulations were characterized using texture analysis (for mechanical and mucoadhesion properties), hydration studies, thermogravimetric analysis (TGA), DSC, X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM).

Results and discussion: DSC showed the eutectic temperature (12.8?°C) of the system where the liquid solution and pure solids both existed at a fixed pressure which helped determine the freeze-annealing cycle at 55?°C for 7?h. Mechanical resistance to compression, hydration and mucoadhesion studies showed that optimized wafers were obtained from aqueous gels containing 2% w/w CAR 911, 4% w/w P407 and 4.4% w/w PEG 600. TGA showed residual water of approximately 1% and SEM showed a porous polymeric network that made ease of hydration possible.

Conclusions: Lyophilized wafers by freeze-drying gels containing 2% w/w CAR 911, 4% w/w P407 and 4.4% w/w PEG 600 with optimum physico-mechanical properties has been achieved.     

Concentration and preservation of very low abundance biomarkers in urine, such as human growth hormone (hGH), by Cibacron Blue F3G-A loaded hydrogel particles

Urine is a potential source of diagnostic biomarkers for detection of diseases, and is a very attractive means of non-invasive biospecimen collection. Nonetheless, proteomic measurement in urine is very challenging because diagnostic biomarkers exist in very low concentration (usually below the sensitivity of common immunoassays) and may be subject to rapid degradation. Hydrogel nanoparticles functionalized with Cibacron Blue F3G-A (CB) have been applied to address these challenges for urine biomarker measurement. We chose one of the most difficult low abundance, but medically relevant, hormones in the urine: human growth hormone (hGH). The normal range of hGH in serum is 1 to 10 ng/mL but the urine concentration is suspected to be a thousand times less, well below the detection limit (50 pg/mL) of sensitive clinical hGH immunoassays. We demonstrate that CB particles can capture, preserve and concentrate hGH in urine at physiological salt and urea concentrations, so that hGH can be measured in the linear range of a clinical immunometric assay. Recombinant and cadaveric hGH were captured from synthetic and human urine, concentrated and measured with an Immulite chemiluminescent immunoassay. Values of hGH less than 0.05 ng/mL (the Immulite detection limit) were concentrated to 2 ng/mL, with a urine volume of 1 mL. Dose response studies using 10 mL of urine demonstrated that the concentration of hGH in the particle eluate was linearly dependent on the concentration of hGH in the starting solution, and that all hGH was removed from solution. Thus if the starting urine volume is 100 mL, the detection limit will be 0.1 pg/mL. Urine from a healthy donor whose serum hGH concentration was 1.34 ng/mL was studied in order detect endogenous hGH. Starting from a volume of 33 mL, the particle eluate had an hGH concentration of 58 pg/mL, giving an estimated initial concentration of hGH in urine of 0.175 pg/mL. The nanotechnology described here appears to have the desired precision, accuracy and sensitivity to support large scale clinical studies of urine hGH levels.