Maleimide-Functionalized Liposomes for Tumor Targeting via In Situ Binding of Endogenous Albumin

Albumin, the most abundant protein in plasma, has been widely used in drug delivery studies. Here, we developed maleimide-functionalized liposomes (Mal-Lip) that can bind to endogenous albumin to improve the tumor targeting efficiency of liposomes. Transmission electron microscopy and gel electrophoresis studies showed that albumin can bind to Mal-Lip due to the chemical coupling of the albumin thiol groups with the maleimide group. Both conventional liposomes and Mal-Lip showed minimal cytotoxicity within the tested range of lipid concentrations, indicating that the maleimide functionality did not increase the toxicity of liposomes to various cells. Mal-Lip was taken up by 4T1 cells to a greater extent than conventional liposomes, and Mal-Lip accumulated in 4T1 tumors in mice more than conventional liposomes after intravenous injection. These results suggest that the maleimide group can improve the tumor targeting efficiency of liposomes in vivo by binding to endogenous albumin in situ. However, the maleimide group also enhanced the uptake of Mal-Lip by Raw264.7 cells and shortened their time in circulation, indicating that further studies should be performed to prevent elimination of Mal-Lip by the immune system.

Unsymmetrical cyanine dye via in vivo hitchhiking endogenous albumin affords high-performance NIR-II/photoacoustic imaging and photothermal therapy

Herein, an unprecedented synergistic strategy for the development of high-performance NIR-II fluorophore is proposed and validated. Based on an unsymmetrical cyanine dye design strategy, the NIR-II emissive dye NIC was successfully developed by replacing only one of the indoline donors of symmetrical cyanine dye ICG with a fully conjugated benz[c,d]indole donor. This minor structural change maximally maintains the high extinction coefficient advantage of cyanine dyes. NIC-ER with endogenous albumin-hitchhiking capability was constructed to further enhance its in vivo fluorescence brightness. In the presence of HSA (Human serum albumin), NIC-ER spontaneously resides in the albumin pocket, and a brilliant ~89-fold increase in fluorescence was observed. Due to its high molar absorptivity and moderate quantum yield, NIC-ER in HSA exhibits bright NIR-II emission with high photostability and significant Stokes shift (>110 nm). Moreover, NIC-ER was successfully employed for tumor-targeted NIR-II/PA imaging and efficient photothermal tumor elimination. Overall, our strategy may open up a new avenue for designing and constructing high-performance NIR-II fluorophores.

Hypoalbuminemia as Surrogate and Culprit of Infections

Hypoalbuminemia is associated with the acquisition and severity of infectious diseases, and intact innate and adaptive immune responses depend on albumin. Albumin oxidation and breakdown affect interactions with bioactive lipid mediators that play important roles in antimicrobial defense and repair. There is bio-mechanistic plausibility for a causal link between hypoalbuminemia and increased risks of primary and secondary infections. Serum albumin levels have prognostic value for complications in viral, bacterial and fungal infections, and for infectious complications of non-infective chronic conditions. Hypoalbuminemia predicts the development of healthcare-associated infections, particularly with Clostridium difficile. In coronavirus disease 2019, hypoalbuminemia correlates with viral load and degree of acute lung injury and organ dysfunction. Non-oncotic properties of albumin affect the pharmacokinetics and pharmacodynamics of antimicrobials. Low serum albumin is associated with inadequate antimicrobial treatment. Infusion of human albumin solution (HAS) supplements endogenous albumin in patients with cirrhosis of the liver and effectively supported antimicrobial therapy in randomized controlled trials (RCTs). Evidence of the beneficial effects of HAS on infections in hypoalbuminemic patients without cirrhosis is largely observational. Prospective RCTs are underway and, if hypotheses are confirmed, could lead to changes in clinical practice for the management of hypoalbuminemic patients with infections or at risk of infectious complications.

In vivotailor-made protein corona of a prodrug-based nanoassembly fabricated by redox dual-sensitive paclitaxel prodrug for the superselective treatment of breast cancer

A PTX-maleimide prodrug nanosystem with enhanced endogenous albumin binding and potent antitumor effect is presented.