Liposomes and transferosomes in the delivery of papain for the treatment of keloids and hypertrophic scars

Pathogenesis, attenuation, and treatment strategies for keloid management

Keloid is an outcome of abnormal cellular response in the wound healing process with excessive fibroblast and collagen deposition in the dermal layer of the skin. It is characterized by a scar showing fibrous outgrowth that grows beyond the original boundaries of the wound. Thus, it is cosmetically and functionally disturbing to the patient. Keloidal development depends on various patient and environmental factors, possibly initiating abnormal wound healing. Due to abnormal wound healing, various aberrant cellular responses are observed during keloid development, like delayed inflammatory response, increased growth factors, varied cytokine level, decreased apoptosis, increased angiogenesis, and imbalanced proteinases. Bacteria and the immune system also play a role in keloid development. Advancements like single-cell RNA sequencing and transcriptomics studies have led to a better understanding of pathogenesis. In line with the complex pathogenesis, the later part of the review covers a detailed analysis of various treatment options employed for keloid, which includes silicone-based topical therapy, drug-based therapy, invasive approach (surgery), and minimally invasive therapies (radiation, laser therapy, and cryotherapy). The advantages and limitations of individual and combination therapies are also discussed. Keloids tend to re-occur after treatment; hence, follow-up is very important, making keloid treatment a complex procedure. Novel therapeutics in keloid have advantages like better efficacy of drugs, less pain, self-administration, and fewer side effects. A few nanotherapeutics advancements, such as microneedles, nanoparticles, liposomes, and exosomes, are discussed in the review.

Preparation, Conformational Structure, and Proteolytic Activity of Papain Covalently Conjugated to Poly(ethylene glycol)-Tethered Lipid Bilayer Membranes

Conjugation of enzymes to lipid membranes is a key approach to reconstitute fascinating features of cell organelles and to deduce the nature of membrane-involved biological events. In this work, papain was covalently conjugated via a cross-linker to phospholipid vesicles (liposomes) tethered with poly(ethylene glycol) (PEG) at 25 °C and pH = 7.0, followed by chromatographic purification. The size of the PEG moiety and the type of cross-linker were optimized to obtain PEG-tethered liposome-conjugated papain (liposome-PEG-papain). Slight conformational changes of the membrane-conjugated papain in both its secondary and tertiary structures were revealed using circular dichroism and intrinsic fluorescence measurements. Notably, heat treatment of a liposome-PEG-papain dispersion at 77 or 84 °C caused permeabilization of the lipid membranes to 5(6)-carboxyfluorescein. Furthermore, liposome-PEG-papain exhibited the digestion activity of casein at 37 °C and pH = 7.6. The structural flexibility of liposomes as enzyme carriers may provide the opportunity to functionalize the membrane-conjugated biomacromolecules.

Development of transferosomes for topical ocular drug delivery of curcumin

BACKGROUND

Transferosomes (TFS) are ultra-deformable elastic bilayer vesicles that have previously been used to enhance gradient driven penetration through the skin. This study aimed to evaluate the potential of TFS for topical ocular drug delivery and to compare their penetration enhancing properties in different ocular tissues.

METHODS

Curcumin-loaded TFS were prepared using Tween 80 as the edge activator. Drug release and precorneal retention of the TFS were evaluated in vitro, while their ocular biocompatibility and bioavailability were evaluated ex vivo using a curcumin solution in medium chain triglycerides as the oily control.

RESULTS

The TFS had a narrow size distribution with a particle size less than 150 nm and an entrapment efficiency greater than 99.96 %. Burst release from the TFS was minimal and the formulation showed good corneal biocompatibility. Moreover, enhanced corneal and conjunctival drug penetration with significantly greater and deeper drug delivery was observed with TFS in all ocular tissues.

CONCLUSION

TFS offer a promising platform for ocular delivery of hydrophobic drugs. This study, for the first time, elucidates the effect of tissue morphology and osmotic gradients on drug penetration in different ocular tissues.

Targeting specific brain districts for advanced nanotherapies: A review from the perspective of precision nanomedicine

Numerous studies are focused on nanoparticle penetration into the brain functionalizing them with ligands useful to cross the blood-brain barrier. However, cell targeting is also crucial, given that cerebral pathologies frequently affect specific brain cells or areas. Functionalize nanoparticles with the most appropriate targeting elements, tailor their physical parameters, and consider the brain's complex anatomy are essential aspects for precise therapy and diagnosis. In this review, we addressed the state of the art on targeted nanoparticles for drug delivery in diseased brain regions, outlining progress, limitations, and ongoing challenges. We also provide a summary and overview of general design principles that can be applied to nanotherapies, considering the areas and cell types affected by the most common brain disorders. We then emphasize lingering uncertainties that hinder the translational possibilities of nanotherapies for clinical use. Finally, we offer suggestions for continuing preclinical investigations to enhance the overall effectiveness of precision nanomedicine in addressing neurological conditions. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Insight into the structural characteristics of self-assembled liposome with epigallocatechin gallate/alcohol dehydrogenase

In this study, the encapsulation and structural characteristics of the self-assembled liposome formed by epigallocatechin gallate (EGCG) and alcohol dehydrogenase (ADH) were studied. According to the results, EGCG significantly increased the catalytic activity of ADH with a 33.33 % activation rate and the liposomes were able to entrap EGCG-ADH with an effectiveness of 88.94 %. The self-assembled monolayers had nanometer-sized particles, and the excellent self-assembled system was demonstrated by the low PDI value and high surface absolute potential. The scanning electron microscope showed that the self-assembled liposome was honeycomb, groove-shaped, and rough. The spectroscopic results showed that EGCG-ADH complex was formed through hydrogen bond, which changed the secondary structure of the liposome, and verified EGCG-ADH liposome system was successfully prepared. In vitro digestion experiments showed that the gastrointestinal tolerance and antioxidant activity of EGCG-ADH liposomes were significantly higher than those of free EGCG-ADH.

The application strategy of liposomes in organ targeting therapy

Liposomes-microscopic phospholipid bubbles with bilayered membrane structure-have been a focal point in drug delivery research for the past 30 years. Current liposomes possess a blend of biocompatibility, drug loading efficiency, prolonged circulation and targeted delivery. Tailored liposomes, varying in size, charge, lipid composition, and ratio, have been developed to address diseases in specific organs, thereby enhancing drug circulation, accumulation at lesion sites, intracellular delivery, and treatment efficacy for various organ-specific diseases. For further successful development of this field, this review summarized liposomal strategies for targeting different organs in series of major human diseases, including widely studied cardiovascular diseases, liver and spleen immune diseases, chronic or acute kidney injury, neurodegenerative diseases, and organ-specific tumors. It highlights recent advances of liposome-mediated therapeutic agent delivery for disease intervention and organ rehabilitation, offering practical guidelines for designing organ-targeted liposomes. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Biology-Inspired Nanomaterials > Lipid-Based Structures.