Skin protein-derived peptide-conjugated vesicular nanocargos for selected skin cell targeting and consequent activation

Advances in active targeting of ligand-directed polymeric nanomicelles via exploiting overexpressed cellular receptors for precise nanomedicine

Many of the utilized drugs which already exist in the pharmaceutical sector are hydrophobic in nature. These drugs are characterized by being poorly absorbed and difficult to formulate in aqueous environments with low bioavailability, which could result in consuming high and frequent doses in order to fulfil the required therapeutic effect. As a result, there is a decisive demand to find modern alternatives to overcome all these drawbacks. Self-assembling polymeric nanomicelles (PMs) with their unique structure appear to be a fascinating choice as a pharmaceutical carrier system for improving the solubility & bioavailability of many drugs. PMs as drug carriers have many advantages including suitable size, high stability, prolonged circulation time, elevated cargo capacity and controlled therapeutic release. Otherwise, the pathological features of some diseased cells, like cancer, allow PMs with particle size <200 nm to be passively uptaken via enhanced permeability and retention phenomenon (EPR). However, the passive targeting approach was proven to be insufficient in many cases. Consequently, the therapeutic efficiency of these PMs can be further reinforced by enhancing their cellular internalization via incorporating targeting ligands. These targeting ligands can enhance the assemblage of loaded cargos in the intended tissues via receptor-mediated endocytosis through exploiting receptors robustly expressed on the exterior of the intended tissue while minimizing their toxic effects. In this review, the up-to-date approaches of harnessing active targeting ligands to exploit certain overexpressed receptors will be summarized concerning the functionalization of the exterior of PMs for ameliorating their targeting potential in the scope of nanomedicine.

Selective Binding of Tannic Acid-Conjugated Lipid Nanovesicles to Proline-Rich Proteins Enhances Transdermal Lipophilic-Antioxidant Delivery

Tannic acid (TA) possesses a notable ability to adhere to proline-rich proteins that make up skin cells and the extracellular matrix (ECM) in the skin tissue. Drug carriers with this specific adhesion ability exhibit improved drug delivery efficiency on the skin. Taking advantage of this, this study presents skin-adhesive TA-conjugated lipid nanovesicles (TANVs) for enhanced transdermal antioxidant delivery. We found that TANVs exhibited selective intermolecular interactions with keratinocyte proline-rich proteins (KPRPs) and collagen that makes up skin cells by hydrogen bonding and van der Waals interactions, further enabling the strong bonding to macroscopic skin itself and ECM. We used vitamin E (α-tocopherol), which is known to effectively reduce oxidative stress but has limited skin penetration, as a drug to verify improved in vitro delivery and therapeutic efficacy. The evaluation revealed that the antioxidant-loaded TANVs exerted excellent scavenging effects against reactive oxygen species induced by ultraviolet light or peroxides in the skin, thereby enabling the development of an active drug delivery system for dermal therapy.

Tumor-targeted liposomes with platycodin D2 promote apoptosis in colorectal cancer

Conventional chemotherapy for colorectal cancer (CRC), though efficacious, is discouraging due to its limited targeting capability, lack of selectivity, and chemotherapy-associated side effects. With the advent of nanomedicines, a liposomal delivery system making use of a combination of anticancer phytochemicals is fast gaining popularity as one of the most promising nanoplatforms for CRC treatment. Rising evidence supports phytochemicals such as platycosides for their anticancer potency. To this end, a combination therapy including tumor-targeted liposomes along with phytochemicals might have a greater therapeutic potential against cancer. In this study, we developed acidity-triggered rational membrane (ATRAM) along with conjugated platycodin D2 (PCD2) and liposomes (PCD2-Lipo-ATRAM) as a tumor-targeting therapy. The PCD2-Lipo-ATRAM treatment demonstrated a successful tumor-targeting ability in the CRC xenografts, in which PCD2 not only exerted a potent antitumor effect by inducing apoptotic cell death and but also functioned as a liposome membrane stabilizer. Moreover, PCD2-Lipo-ATRAM suppressed antiapoptotic BCL-2 family proteins, resulting in enhanced cytotoxicity toward CRC cells by inducing intrinsic caspase-9/-3 mediated apoptosis. Thus, our data has shown that tumor-targeting PCD2-based liposomal systems represent a promising strategy for CRC therapy, since they directly target the tumors, unlike other therapies that can miss the target.

Fibroblast-targeting polymeric nanovehicles to enhance topical wound healing through promotion of PAR-2 receptor-mediated endocytosis

The level of collagen production critically determines skin wound contraction. If an intelligent skin drug delivery technology that enables collagen production in a specific wound skin area is developed, a breakthrough in wound healing treatment would be expected. However, such an intelligent drug delivery technology has not yet been developed as much as in the field of anticancer therapy. In this study, we propose a smart drug delivery system using polymeric nanovehicles (PNVs), in which the periphery is conjugated with a fibroblast-targeting collagen-derived peptide, KTTKS (Lys-Thr-Thr-Lys-Ser). We showed that surface engineering of PNVs with simultaneous PEGylation and peptide patching improved the dispersibility of PNVs, while promoting selective cellular uptake to fibroblasts via PAR-2 receptor-mediated endocytosis. In vitro collagen production and in vivo wound healing assays revealed that curcumin-loaded fibroblast-targeting PNVs significantly enhanced collagen production and wound healing activities, thus promising effective skin tissue regeneration.

Facile and scalable fabrication of exosome-mimicking nanovesicles through PEGylated lipid detergent-aided cell extrusion

We report a scalable fabrication method to generate exosome-mimicking nanovesicles (ENVs) by using a biocompatible, cell-binding lipid detergent during cell extrusion. A PEGylated mannosylerythritol lipid (MEL_PEG) detergent was rationally engineered to strongly associate with phospholipid membranes to increase cell membrane deformability and the corresponding friction force during extrusion and to enhance the dispersibility of ENVs. Compared to cell extrusion without detergent, cell extrusion in the presence of MEL_PEG increased the ENV production yield by approximately 20 times and cellular protein content per MEL_PEG-functionalized ENV by approximately 2-fold relative to that of unmodified ENVs. We verified that MEL_PEG strongly binds to ENV membranes and increases membrane deformability via expansion/swelling while preserving the integrity of the phospholipid bilayer structure. The results highlight that the MEL_PEG-aided cell extrusion process broadly applies to various cell lines; hence, it could be helpful in the production of ENVs for tissue regeneration, drug delivery, and cancer nanomedicine.

Polyphenol-Modified Nanovesicles for Synergistically Enhanced in vitro Tumor Cell Targeting and Apoptosis

Tannic acid (TA) not only prevents drug carriers from sticking to the glycocalyx layer of vascular endothelial cells but also has anti-cancer attributes, thereby improving drug delivery efficiency in cancer...