Lighting the Path: Light Delivery Strategies to Activate Photoresponsive Biomaterials In Vivo

Photoresponsive biomaterials are experiencing a transition from in vitro models to in vivo demonstrations that point toward clinical translation. Dynamic hydrogels for cell encapsulation, light-responsive carriers for controlled drug delivery, and nanomaterials containing photosensitizers for photodynamic therapy are relevant examples. Nonetheless, the step to the clinic largely depends on their combination with technologies to bring light into the body. This review highlights the challenge of photoactivation in vivo, and presents strategies for light management that can be adopted for this purpose. The authors’ focus is on technologies that are materials-driven, particularly upconversion nanoparticles that assist in “direct path” light delivery through tissue, and optical waveguides that “clear the path” between external light source and in vivo target. The authors’ intention is to assist the photoresponsive biomaterials community transition toward medical technologies by presenting light delivery concepts that can be integrated with the photoresponsive targets. The authors also aim to stimulate further innovation in materials-based light delivery platforms by highlighting needs and opportunities for in vivo photoactivation of biomaterials.     

Tailored-Made Polydopamine Nanoparticles to Induce Ferroptosis in Breast Cancer Cells in Combination with Chemotherapy

Ferroptosis is gaining followers as mechanism of selective killing cancer cells in a non-apoptotic manner, and novel nanosystems capable of inducing this iron-dependent death are being increasingly developed. Among them, polydopamine nanoparticles (PDA NPs) are arousing interest, since they have great capability of chelating iron. In this work, PDA NPs were loaded with Fe³⁺ at different pH values to assess the importance that the pH may have in determining their therapeutic activity and selectivity. In addition, doxorubicin was also loaded to the nanoparticles to achieve a synergist effect. The in vitro assays that were performed with the BT474 and HS5 cell lines showed that, when Fe³⁺ was adsorbed in PDA NPs at pH values close to which Fe(OH)₃ begins to be formed, these nanoparticles had greater antitumor activity and selectivity despite having chelated a smaller amount of Fe³⁺. Otherwise, it was demonstrated that Fe³⁺ could be released in the late endo/lysosomes thanks to their acidic pH and their Ca²⁺ content, and that when Fe³⁺ was co-transported with doxorubicin, the therapeutic activity of PDA NPs was enhanced. Thus, reported PDA NPs loaded with both Fe³⁺ and doxorubicin may constitute a good approach to target breast tumors.     

Structural Aspects of P2-Type Na0.67Mn0.6Ni0.2Li0.2O2 (MNL) Stabilization by Lithium Defects as a Cathode Material for Sodium-Ion Batteries

A known strategy for improving the properties of layered oxide electrodes in sodium-ion batteries is the partial substitution of transition metals by Li. Herein, the role of Li as a defect and its impact on sodium storage in P2-Na_0.67Mn_0.6Ni_0.2Li_0.2O₂ is discussed. In tandem with electrochemical studies, the electronic and atomic structure are studied using solid-state NMR, operando XRD, and density functional theory (DFT). For the as-synthesized material, Li is located in comparable amounts within the sodium and the transition metal oxide (TMO) layers. Desodiation leads to a redistribution of Li ions within the crystal lattice. During charging, Li ions from the Na layer first migrate to the TMO layer before reversing their course at low Na contents. There is little change in the lattice parameters during charging/discharging, indicating stabilization of the P2 structure. This leads to a solid-solution type storage mechanism (sloping voltage profile) and hence excellent cycle life with a capacity of 110 mAh g^-1 after 100 cycles. In contrast, the Li-free compositions Na_0.67Mn_0.6Ni_0.4O₂ and Na_0.67Mn_0.8Ni_0.2O₂ show phase transitions and a stair-case voltage profile. The capacity is found to originate from mainly Ni³⁺/Ni⁴⁺ and O^2-/O^2-δ redox processes by DFT, although a small contribution from Mn⁴⁺/Mn⁵⁺ to the capacity cannot be excluded.     

Use of citric acid for heavy metals extraction from contaminated sewage sludge for land application.

Recent studies revealed that organic acids such as citric and oxalic acids seemed to be more promising as chemical extracting agents for removal of heavy metals from contaminated sludge, since they are biodegradable and can attain a higher metal extraction efficiency at mildly acidic pH compared to other extracting agents. Results of a lab-scale study on the efficiency of citric acid in the extraction of chromium (Cr), copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) from anaerobically digested sludge, revealed that citric acid seemed to be highly effective in extracting Cr (at 100%), Cu (at 88%), Ni (at 98%) and Zn (at 100%) at pH 2.33, mostly at 5 days leaching time except for Cu and Zn, which are at 1 day and 2 h contact times respectively. Lead removal at the same pH was also high at 95% but at a longer leaching time of 11 days. At pH 3, citric acid seemed to be highly effective in extracting Pb (at 100%) at 1 day leaching time, although higher removals were also attained for Ni (70%) and Zn (80%) at only 2 h leaching time. Chemical speciation studies showed that Cr, Cu and Ni in the sludge sample seem to predominate in residual fractions, while Pb and Zn were found mostly bound to organic and inorganic matter forms, hence the potential of the sludge for land application.     

Fetal alcohol syndrome in twins of alcoholic mothers: concordance of diagnosis and IQ

The effects of teratogens can be modified by genetic differences in fetal susceptibility and resistance. Twins of alcoholic mothers provide a unique opportunity to study this phenomenon with respect to alcohol teratogenesis. Sixteen pairs of twins, 5 MZ and 11 DZ, all heavily exposed to alcohol prenatally, were evaluated. They represented all available twins of alcohol-abusing mothers who were on the patient rolls of the authors. The rate of concordance for diagnosis was 5/5 for MZ and 7/11 for DZ twins. In two DZ pairs, one twin had fetal alcohol syndrome (FAS), while the other had fetal alcohol effects (FAE). In 2 other DZ pairs, one twin had no diagnosis while one had FAE. IQ scores were most similar within pairs of MZ twins and least similar within pairs of DZ twins discordant for diagnosis. Despite equivalent alcohol exposure within twin pairs, alcohol teratogenesis appears to be more uniformly expressed in MZ than in DZ twins. These data are interpreted as reflecting the modulating influence of genes in the expression of the teratogenic effects of alcohol.     

Cardiac tamponade as a presentation of primary hypothyroidism in a young woman

Pericardial effusion (PE) as a hypothyroidism associated sign, is something that can be found with relative frequency; nevertheless, cardiac tamponade (CT) as the first sign of this disease may be considered exceptional especially in young patients. We report a 31 years old woman with clinical symptoms and signs of CT that in the forward workshop was diagnosed of primary hypothyroidism as cause of the CT. We shortly describe the case and review the literature, emphasizing the importance of the knowledge of CT trigger factors in myxedematous PE, as well as its usual benign evolution with hormonal treatment, without recurrences of the CT after pericardiocentesis is performed. This justify a conservative approach, in spite of the slow resolution of the PE what can take as long as 1.5 years.     

Partial congenital defect of the left pericardium: angiographic diagnosis and treatment by thoracoscopic pericardiectomy: case report

Twenty-six patients with an intracardiac myxoma underwent surgical resection at our institution from 1977 through 1992. Left atrial myxoma was diagnosed in 22 patients, left ventricular in 1, right atrial in 2, and right ventricular in 1. Six patients were asymptomatic; preoperative symptoms included dyspnea, arrhythmias, embolic episodes, and syncope. The diagnosis was established with transthoracic echocardiography in all cases but one. Surgery was performed in all cases with the aid of cardiopulmonary bypass with moderate hypothermia and cold crystalloid cardioplegia. One patient with a left ventricular myxoma died in a comatose state during the immediate postoperative period. Long-term clinical and echocardiographic evaluation was performed in 19 patients; results were excellent (all the patients were in New York Heart Association functional class I or II), and no recurrences were documented. The clinical characteristics, diagnostic methods, and surgical approach are presented and discussed.