Surgical Retrieval,Isolation and In vitro Expansion of Human Anterior Cruciate Ligament-derived Cells for Tissue Engineering Applications

Injury to the ACL is a commonly encountered problem in active individuals. Even partial tears of this intra-articular knee ligament lead to biomechanical deficiencies that impair function and stability. Current options for the treatment of partial ACL tears range from nonoperative, conservative management to multiple surgical options, such as: thermal modification, single-bundle repair, complete reconstruction, and reconstruction of the damaged portion of the native ligament. Few studies, if any, have demonstrated any single method for management to be consistently superior, and in many cases patients continue to demonstrate persistent instability and other comorbidities.The goal of this study is to identify a potential cell source for utilization in the development of a tissue engineered patch that could be implemented in the repair of a partially torn ACL. A novel protocol was developed for the expansion of cells derived from patients undergoing ACL reconstruction. To isolate the cells, minced hACL tissue obtained during ACL reconstruction was digested in a Collagenase solution. Expansion was performed using DMEM/F12 medium supplemented with 10% fetal bovine serum (FBS) and 1% penicillin/streptomycin (P/S). The cells were then stored at -80 ºC or in liquid nitrogen in a freezing medium consisting of DMSO, FBS and the expansion medium. After thawing, the hACL derived cells were then seeded onto a tissue engineered scaffold, PLAGA (Poly lactic-co-glycolic acid) and control Tissue culture polystyrene (TCPS). After 7 days, SEM was performed to compare cellular adhesion to the PLAGA versus the control TCPS. Cellular morphology was evaluated using immunofluorescence staining. SEM (Scanning Electron Microscope) micrographs demonstrated that cells grew and adhered on both PLAGA and TCPS surfaces and were confluent over the entire surfaces by day 7. Immunofluorescence staining showed normal, non-stressed morphological patterns on both surfaces. This technique is promising for applications in ACL regeneration and reconstruction.     

Modulation of Aggregation Propensity of Aβ38 by Site Specific Multiple Proline Substitution

Proline with its unique geometrical feature generates turn in the peptide backbone. Therefore, aggregation potential of Aβ38 can be modulated by insertion of proline at specific positions. Although site specific proline mutation is reported, effect of multiple proline substitution on aggregation potential is still not demonstrated. Therefore, Aβ38, a single proline substituted variant, V18P-Aβ38, a double proline substituted variant, V18P-I31P-Aβ38 and a triple proline substituted version, V12P-V18P-I31P-Aβ38 were synthesized and their aggregation potential were studied. The proline mutants found to have higher solubility and slower aggregation kinetics. The double mutated version was relatively less aggregation prone than its single mutated version. Such analogues can be useful for designing new β sheet breaker peptides, studying the mechanism of aggregation and structural analyses.     

Senescence of Hydrilla leaves in light and darkness

Senescence of isolated leaves of Hydrilla verticillata (L.f.) Royle was studied in both darkness and light (20 μmol m⁻² s⁻¹). Senescence in the dark followed a general pattern of deterioration, i.e., gradual loss of cellular macromolecules like chlorophyll, protein and RNA with a concomitant rise in α-amino nitrogen, protease activity and tissue permeability. In light, however, an accelerated loss of chlorophyll took place although protein loss and increase in protease activity were retarded. A higher level of α-amino nitrogen in leaves in the light than in darkness could be correlated with lower leaching of free amino acids in light. Light decreased tissue permeability, as evidenced by lower conductivity of the incubation medium. In the light, RNA increased over the initial level. Both soluble and insoluble carbohydrates declined in the dark. The decline of insoluble carbohydrate was retarded by light, whereas soluble carbohydrate showed an initial rise and then declined sharply in the light.     

Highly Efficient Perovskite Solar Cell Photocharging of Lithium Ion Battery Using DC–DC Booster

Solar cells become a viable energy source to charge lithium ion batteries. Here a simple and efficient photocharging design approach is demonstrated, where a promising low cost single junction solar cell such as perovskite solar cell or dye sensitized solar cell efficiently charges a Li₄Ti₅O₁₂‐LiCoO₂ Li‐ion cell using a DC–DC voltage boost converter. The converter boosts the low input voltage of a single junction solar cell to charge a lithium ion cell and offers advantages including maximum power point tracking of solar photovoltaics and overvoltage protection for the lithium ion cell. This is the first demonstration of this technology. This approach leads to the highest reported overall efficiency of 9.36% and average storage efficiency of 77.2% at 0.5 C discharge for a perovskite solar cell‐converter charging. The high efficiency for the perovskite solar cell‐converter charging is attributed to maximum power harvesting along with high power conversion efficiency of the perovskite solar cell and low potential polarization between the charge and discharge voltage plateaus for the Li₄Ti₅O₁₂‐LiCoO₂ Li‐ion cell.