Single-Cell Microgels for Diagnostics and Therapeutics

Cell encapsulation within hydrogel droplets is transforming what is feasible in multiple fields of biomedical science such as tissue engineering and regenerative medicine, in vitro modeling, and cell-based therapies. Recent advances have allowed researchers to miniaturize material encapsulation complexes down to single-cell scales, where each complex, termed a single-cell microgel, contains only one cell surrounded by a hydrogel matrix while remaining <100 μm in size. With this achievement, studies requiring single-cell resolution are now possible, similar to those done using liquid droplet encapsulation. Of particular note, applications involving long-term in vitro cultures, modular bioinks, high-throughput screenings, and formation of 3D cellular microenvironments can be tuned independently to suit the needs of individual cells and experimental goals. In this progress report, an overview of established materials and techniques used to fabricate single-cell microgels, as well as insight into potential alternatives is provided. This focused review is concluded by discussing applications that have already benefited from single-cell microgel technologies, as well as prospective applications on the cusp of achieving important new capabilities.     

Resveratrol as Chemosensitizer Agent: State of Art and Future Perspectives

Resistance to chemotherapy still remains a major challenge in the clinic, impairing the quality of life and survival rate of patients. The identification of unconventional chemosensitizing agents is therefore an interesting aspect of cancer research. Resveratrol has emerged in the last decades as a fascinating molecule, able to modulate several cancer-related molecular mechanisms, suggesting a possible application as an adjuvant in cancer management. This review goes deep into the existing literature concerning the possible chemosensitizing effect of resveratrol associated with the most conventional chemotherapeutic drugs. Despite the promising effects observed in different cancer types in in vitro studies, the clinical translation still presents strong limitations due to the low bioavailability of resveratrol. Recently, efforts have been moved in the field of drug delivery to identifying possible strategies/formulations useful for a more effective administration. Despite the necessity of a huge implementation in this research area, resveratrol appears as a promising molecule able to sensitize resistant tumors to drugs, suggesting its potential use in therapy-refractory cancer patients.     

Antibacterial and photocatalytic behaviour of green synthesis of Zn0.95Ag0.05O nanoparticles using herbal medicine extract

The present work aimed to synthesize Zn_0.95Ag_0.05O (ZnAgO) nanoparticles using rosemary leaf extracts as a green chemistry method. The characterization of Ag-doped ZnO nanoparticles was performed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and ultraviolet–visible spectrophotometry (UV–visible). The XRD, FTIR, and UV–visible spectra confirmed the formation of the presence of hexagonal ZnAgO nanoparticles. FESEM micrograph shows that the nanoparticles have been distributed homogeneously and uniformly. The morphology of ZnAgO nanoparticles is quasi-spherical configuration. Also, the mean particle size is in the range of 22–40 nm. The photocatalytic degradation of methylene blue in the presence of Ag-doped ZnO nanoparticles is nearly 98.5% after exposing 100 min. The ultraviolet lamp was used as the light source for photocatalyst degradation. The disc diffusion method was chosen to study the antibacterial activity of as-synthesized ZnAgO nanoparticles. Antibacterial activity of Zn_0.95Ag_0.05O nanoparticles against Staphylococcus aureus and Escherichia coli revealed that the as-synthesized ZnAgO nanoparticles were efficient in inhibition of bacterial growth.     

Characterization of Dog Glutathione Transferase P1-1, an Enzyme Relevant to Veterinary Medicine

Glutathione transferases (GSTs) form a family of detoxication enzymes instrumental in the inactivation and elimination of electrophilic mutagenic and carcinogenic compounds. The Pi class GST P1-1 is present in most tissues and is commonly overexpressed in neoplastic cells. GST P1-1 in the dog, Canis lupus familiaris, has merits as a marker for tumors and as a target for enzyme-activated prodrugs. We produced the canine enzyme CluGST P1-1 by heterologous bacterial expression and verified its cross-reactivity with antihuman-GST P1-1 antibodies. The catalytic activity with alternative substrates of biological significance was determined, and the most active substrate found was benzyl isothiocyanate. Among established GST inhibitors, Cibacron Blue showed positive cooperativity with an IC₅₀ value of 43 nM. Dog GST P1-1 catalyzes activation of the prodrug Telcyta, but the activity is significantly lower than that of the human homolog.     

中医药膳与特膳食品产业融合发展思辨

中医药膳与特膳食品一样,均能为特定人群系统定量地提供特殊或针对性的生理物质与营养成分,从而改善特定人群的营养基础代谢,减少不必要的代谢负担。文章提出在健康中国战略背景下加强特膳食品与中医药膳产业融合发展的必要性及发展的瓶颈,并指出两者融合发展的有效路径。     

中国与日本兽药残留限量标准比较分析研究

目的研究我国与日本兽药残留限量标准的异同。方法根据中华人民共和国国农业部第235号公告以及日本肯定列表、厚生劳动省第370号公告,比较两国法律法规涉及的禁用与限量物质清单在兽药种类、残留食品种类、残留限量指标值等方面的异同。结果我国兽药残留限量标准涉及123种兽药、3大类食品、12种动物与9种靶组织、550个限量指标,日本则涉及243种兽药、4大类食品、16种动物与8种靶组织、3705个限量指标。两者相比,我国83种兽药与日本相同, 445个限量指标与日本810个限量指标具有可比性。在中日标准涉及的具有可比性的限量指标中,我国有215个指标与日本等同,有80个指标比日本严格,有139个指标比日本宽松。结论在兽药残留限量标准涉及的可比指标值方面,我国二分之一的指标值与日本对应指标值是等同的。     

高效液相色谱-串联质谱法测定中草药中多种 新烟碱类农药的残留量

目的建立液相色谱-串联质谱分析法同时测定中草药夏枯草、野菊花、金银花、苏银花中噻虫嗪、氯噻啉、吡虫啉、啶虫脒、噻虫胺、噻虫啉6种新烟碱类农药残留量。方法样品中的6种新烟碱类杀虫剂经乙腈提取,QuEChERS方法净化后,液相色谱-串联质谱法分离和测定,外标法定量。结果方法检出限为0.1～4.8μg/kg,在方法的检测限与200 ng/mL测定范围内有良好的线性关系(r0.9990),在所添加5个水平浓度下,方法的回收率在70.4%～108.3%,相对标准偏差在1.0%～8.8%。结论该方法准确、简单、快速,适用于中草药中多种新烟碱类农药的同时检测。     

QuEChERS结合高效液相色谱-串联质谱法同时测定黄颡鱼中7种染料类兽药残留

目的建立黄颡鱼中孔雀石绿、隐色孔雀石绿、结晶紫、隐色结晶紫、亚甲基蓝、天青A、天青B残留量检测的QuEChERS-高效液相色谱-串联质谱(high performanc eliquid chromatography-tandem mass spectrometry, HPLC-MS/MS)联用方法。方法样品中加入乙腈于-18℃冷冻30 min,再加入去水剂无水硫酸镁和氯化钠,漩涡振荡离心后取上清液加入净化萃取试剂,漩涡离心后氮气吹至近干,乙腈复溶并注入HPLC-MS/MS测试。结果在最优的条件下, 7种染料类兽药在0.1～10 ng/mL范围内线性关系良好,方法平均回收率为78.2%～95.3%,精密度为3.0%～5.6%。结论该方法简单、快速、可靠,线性关系良好,检出限低,灵敏度高,可用于黄颡鱼中7种染料类兽药残留测定。     

Cell-free Stem Cell-Derived Extract Formulation for Regenerative Medicine Applications

Stem cells for regenerative medicine purposes offer therapeutic benefits, but disadvantages are still ill defined. The benefit of stem cells may be attributed to their secretion of growth factors (GFs), cytokines (CKs), and extracellular vesicles (EVs), including exosomes. We present a novel cell-free stem cell-derived extract (CCM), formulated from human progenitor endothelial stem cells (hPESCs), characterized for biologically active factors using ELISA, nanoparticle tracking analysis and single particle interferometric reflectance imaging sensing. The effect on fibroblast proliferation and ability to induce stem cell migration was analyzed using Alamar Blue proliferation and Transwell migration assays, respectively. GFs including IGFBP 1, 2, 3, and 6, insulin, growth hormone, PDGF-AA, TGF-α, TGF-β1, VEGF, and the anti-inflammatory cytokine, IL-1RA were detected. Membrane enclosed particles within exosome size range and expressing exosome tetraspanins CD81 and CD9 were identified. CCM significantly increased cell proliferation and induced stem cell migration. Analysis of CCM revealed presence of GFs, CKs, and EVs, including exosomes. The presence of multiple factors including exosomes within one formulation, the ability to promote cell proliferation and induce stem cell migration may reduce inflammation and pain, and augment tissue repair.