Diseleno-albumin, a native bio-inspired drug free therapeutic protein induces apoptosis in lung cancer cells through mitochondrial oxidation.

Macromolecular therapeutic is the emerging concept in the fields of drug delivery and drug discovery. The present study reports the design and development of a serum albumin based macromolecular chemotherapeutic by conjugating bovine serum albumin (BSA) with 3,3'-diselenodipropionic acid (DSePA), a pharmacologically active organo-diselenide (R-Se-Se-R). The reaction conditions were optimised to achieve the controlled conjugation of BSA with DSePA without causing any significant alteration in its physico-chemical properties or secondary structure and crosslinking. The chemical characterisation of the reaction product through various spectroscopic techniques viz., FT-IR, Raman, XPS, AAS and MALDI-TOF-MS, established the conjugation of about ∼5 DSePA molecules per BSA molecule. The DSePA conjugated BSA (Se-Se-BSA) showed considerable stability in aqueous and lyophilized forms. The cytotoxicity studies by involving cell lines of cancerous and non-cancerous origins indicated that Se-Se-BSA selectively inhibited the proliferation of cancerous cells. The cellular uptake studies by physically labelling Se-Se-BSA with curcumin and following its intracellular fluorescence confirmed that uptake efficiency of Se-Se-BSA was almost similar to that of native BSA. Finally, studies on the mechanism of action of Se-Se-BSA in the A549 (lung adenocarcinoma) cells revealed that it induced mitochondrial ROS generation followed by mitochondrial dysfunction, activation of caspases and apoptosis. Together, these results demonstrate a bio-inspired approach of exploring diselenide (-Se-Se-) grafted serum albumin as the potential drug free therapeutic for anticancer application.

Balancing loading, cellular uptake, and toxicity of gelatin-pluronic nanocomposite for drug delivery: Influence of HLB of pluronic.

In this study, pluronic stabilized gelatin nanocomposite of varying hydrophilic-lipophilic balance (HLB) were synthesized to study the effect of surface hydrophobicity on their cellular uptake and in turn the delivery of a model hydrophobic bioactive compound, curcumin (CUR). Notably, the variation in HLB from 22 to 8 did not cause much change in morphology (~spherical) and surface charge (~ -6.5 mV) while marginally reducing the size of nanocomposite from 165 ± 097 nm to 134 ± 074 nm. On contrary, nanocomposites exhibited a very significant increase in their numbers, hydrophobicity as well as CUR loading with decreasing HLB values (22-8) of pluronic. Further, the cellular uptake of CUR through pluronic-gelatin nanocomposites was studied in human lung carcinoma (A549) cells. The results indicated that cellular uptake of CUR through nanocomposites followed the order HLB 22 > HLB 18 > HLB 15 > HLB 8. This was also reflected in terms of the decrease in cytotoxicity of CUR through nanocomposite of HLB 8 as compared to that of HLB 22. Interestingly, bare nanocomposite of HLB 8 showed significantly higher cytotoxicity as compared to that of HLB 22. Together these results suggested that although higher hydrophobicity of the gelatin-pluronic nanocomposite facilitated higher entrapment of CUR, the carrier per se became toxic due to its hydrophobic interaction with lipid bilayer of plasma membrane. Thus, HLB parameter is very important in designing hybrid nanocomposite systems involving protein and pluronic to ensure both bio-compatibility of the carrier and the optimum cellular delivery of the pay load.

Gelatin-lecithin-F127 gel mediated self-assembly of curcumin vesicles for enhanced wound healing.

Curcumin, a principal component of Curcuma longa, has a long history of being used topically for wound healing. However, poor aqueous solubility of curcumin leads to poor topical absorption. Recently, gelatin based gel has been reported to overcome this issue. However, the release of curcumin from gelatin gel in the bioavailable or easily absorbable form is still a challenge. The present study reports the development of a composite gel prepared from gelatin, F127 and lecithin using temperature dependant gelation and loading of curcumin within it. Notably, the composite gel facilitated the release of curcumin entrapped within vesicles of ~400 nm size. Further, the composite gel exhibited increase in the storage modulus or gel strength, stability, pore size and hydrophobicity as compared to only gelatin gel. Finally, wound healing assay in murine model indicated that curcumin delivered through composite gel showed a significantly faster healing as compared to that delivered through organic solvent. This was also validated by histopathological and biochemical analysis showing better epithelization and collagen synthesis in the group dressed with curcumin containing composite gel. In conclusion, composite gel facilitated the release of bioavailable or easily absorbable curcumin which in turn enhanced the wound healing.

Preparation of a size selective nanocomposite through temperature assisted co-assembly of gelatin and pluronic F127 for passive targeting of doxorubicin.

The preparation of a water dispersible and pH responsive gelatin-F127 nanocomposite using a thermal relaxation approach is reported. The results indicated that physical properties (size and surface charge) of the gelatin-F127 nanoparticle can be tuned by varying the F127 to gelatin weight ratio. The heating (60 °C) of a saline solution (pH 7.4) containing 0.5% (w/v) of gelatin and 20% (w/w of gelatin) of F127 followed by gradual cooling at room temperature yielded nanoparticles of desired size (160 ± 40 nm), viscosity (1.36 ± cP) and surface charge (-6.47 ± 0.7 mV). The drug delivery application of nanocarriers was investigated using doxorubicin hydrochloride (Dox) as a model drug. These nanocarriers showed high encapsulation efficiency of Dox (85%), a sustained release profile, and substantial cellular internalization. Additionally, Dox loaded nanocarriers (G-Dox) exhibited prolonged residence in blood as evidenced by their longer circulation time as compared to plain Dox. Moreover, G-Dox exhibited a higher availability of the drug in plasma as compared to nonspecific organs such as the heart, liver and kidneys, highlighting its significance in reducing drug associated side effects. Finally, the enhanced toxicity of G-Dox to a WEHI-164 (fibrosarcoma) tumor model as compared to that of plain Dox under an identical dosage of 6 mg per kg body weight (IP) confirmed its potential for chemotherapy application.