Biodegradable calcium carbonate carriers for the topical delivery of clobetasol propionate.

Inflammatory dermatoses represent a global problem with increasing prevalence and recurrence among the world population. Topical glucocorticoids (GCs) are the most commonly used anti-inflammatory drugs in dermatology due to a wide range of their therapeutic actions, which, however, have numerous local and systemic side effects. Hence, there is a growing need to create new delivery systems for GCs, ensuring the drug localization in the pathological site, thus increasing the effectiveness of therapy and lowering the risk of side effects. Here, we propose a novel topical particulate formulation for the GC clobetasol propionate (CP), based on the use of porous calcium carbonate (CaCO3) carriers in the vaterite crystalline form. The designed carriers contain a substantially higher CP amount than conventional dosage forms used in clinics (4.5% w/w vs. 0.05% w/w) and displayed a good biocompatibility and effective cellular uptake when studied in fibroblasts in vitro. Hair follicles represent an important reservoir for the GC accumulation in skin and house the targets for its action. In this study, we demonstrated successful delivery of the CP-loaded carriers (CP-CaCO3) into the hair follicles of rats in vivo using optical coherent tomography (OCT). Importantly, the OCT monitoring revealed the gradual intrafollicular degradation of the carriers within 168 h with the most abundant follicle filling occurring within the first 48 h. Biodegradability makes the proposed system especially promising when searching for new CP formulations with improved safety and release profile. Our findings evidenced the great potential of the CaCO3 carriers in improving the dermal bioavailability of this poorly water-soluble GC.

Luminescent alloyed quantum dots for turn-off enzyme-based assay.

A new bioanalytical labeling system based on alloyed quantum dots' (QDs) photoluminescence quenching caused by an enzymatic reaction has been developed and tested for the first time. The catalytic role of the enzyme provides high sensitivity and the possibility of varying detecting time to improve assay sensitivity. Alloyed luminescent QDs were chosen in view of their small size (5-7 nm) and the high sensitivity of their optical properties to physicochemical interactions. Here, we described the synthesis of alloyed luminescent QDs and demonstrated the possibility of using them as a luminescent turn-off substrate for enzymatic assay. Synthesized alloyed QDs were found to be a sensitive turn-off substrate for glucose oxidase in homogeneous and heterogeneous assay models. CdZnSeS and CdZnSeS/ZnS QDs covered with dihydrolipoic acid and 2-mercaptoethanol were tested. A glucose oxidase limit of detection of 6.6 nM for the heterogenous high-throughput model assay was reached.

Molecularly imprinted polyaniline for detection of horseradish peroxidase.

A new facile and fast approach to the synthesis of polyaniline (PANi) molecularly imprinted polymers (MIPs) based on aniline oxidative chemical polymerization was proposed for protein recognition. For the first time, a surface imprinting strategy was implemented for the synthesis of PANi MIPs on the inner surface of soft glass polycapillaries (PC) with a large (2237) number of individual microcapillaries. Two different PANi layers-(i) PANi film and (ii) protein imprinted PANi nanowires-were synthesized sequentially. Uniform and highly stable PANi film was synthesized by oxidative polymerization at pH< 1. The synthesis of PANi MIPs on the PANi film pre-coated surface improved the reproducibility of PANi MIP formation. PANi MIP nanowires were synthesized at "mild" conditions (pH > 4.5) to preserve the protein template activity. The binding of horseradish peroxidase (HRP) molecules on the PANi MIP selective sites was confirmed by photometry (TMB chromogenic reaction), SEM images, and FTIR spectroscopy. The developed PANi MIPs enable HRP determination with a limit of detection (LOD) as low as 1.00 and 0.07 ng mL-1 on the glass slips and PC, respectively. The PANi MIPs are characterized by high stability; they are reversible and selective to HRP. The proposed approach allows PANi MIPs to be obtained for proteins on different supports and to create new materials for separation and sensing. Graphical abstract.

Soft glass multi-channel capillaries as a platform for bioimprinting.

Multi-channel capillaries (MC) formed from thousands individual microcapillaries with diameters ranging 10-100 µm are of a great interest for their use as platforms for molecular imprinting due to their relatively large surface area, high mechanical stability and possibility of facile integration in sensor systems. The manuscript proposes a new format of immunoassay based on imprinted protein immobilized on a MC inner surface modified with poly-l-lysine. The combination of the environmentally friendly, easy-to-produce and cheap recognition element with the carrier allowing to increase the assay sensitivity makes the described technique a perspective alternative for the existing screening tests. Two bioimprinting approaches were described. The imprinted protein (ovalbumin, OVA) primarily prepared separately and later immobilized on a MC structure was compared to the imprinted OVA directly prepared on the MC surface. Detection of a food contaminant zearalenone was chosen as a proof-of-concept. In a case of the immobilization of the primarily prepared imprinted OVA the reached limit of detection (LOD) was 0.8 ng/mL, and for the in-situ imprinted OVA the LOD was 0.12 ng/mL. The sensitivity of the developed bioimprinted assay was comparable to the commercially available ELISA kits for ZEN detection. The OVA in-situ imprinted on the MC surface was tested for the detection of ZEN in artificially spiked wheat samples. The high recovery values (88-112%) and good repeatability (RSD of 8.5-9.6%) were demonstrated allowing to conclude that the IPs-based MC-ELISA is a promising tool for analysis of the mycotoxin in complex matrices.

Simultaneous determination of proteins in microstructured optical fibers supported by chemometric tools.

A new perspective on the relevant problem-creating simple, rapid, and efficient protein sensors based on microstructured optical fibers using a simple homogeneous analysis format-was proposed. Commercially available long-period grating hollow core microstructured optical fibers (LPG HCMOF) were used to determine bovine serum albumin (BSA) and albumin from chicken eggs (OVA) in binary mixtures as well as immunoglobulin G (IgG) in the presence of BSA and OVA. LPG HCMOF transmission spectra allowed the detection of both BSA and OVA up to 10 mg/mL with LOD as low as 0.1 and 0.8 µg/mL, respectively. Partial least squares regression (PLS) was utilized for modeling of LPG HCMOF spectral data and quantitative analysis of BSA, OVA, total protein, and IgG in binary and ternary mixtures. Rather high coefficients of determination (R2) and low root mean square error for the calibration (RMSEC) (15%) and prediction (RMSEP) (20%) were obtained for all PLS models. The proposed approach was tested in the analysis of BSA in spiked horse blood hemolyzed (HBH). The results demonstrated the functionality of the proposed approach and offered the opportunity for the creation of a wide range of sensors for protein determination in complex mixtures. Graphical abstract.