Engineering protein particles for pulmonary drug delivery

Conformational Transitions upon Maturation Rule Surface and pH-Responsiveness of α-Lactalbumin Microparticulates

De novo designed protein supramolecular structures are nowadays attracting much interest as highly performing biomaterials. While a clear advantage is provided by the intrinsic biocompatibility and biodegradability of protein and peptide building blocks, developing sustainable and green bottom up approaches for finely tuning the material properties still remains a challenge. Here, we present an experimental study on the formation of protein microparticles in the form of particulates from the protein α-lactalbumin using bulk mixing in water solution and high temperature. Once formed, the structure and stability of these spherical protein condensates change upon further thermal incubation while the size of aggregates does not significantly increase. Combining advanced microscopy and spectroscopy methods, we prove that this process, named maturation, is characterized by a gradual increase of amyloid-like structure in protein particulates, an enhancement in surface roughness and in molecular compactness, providing a higher stability and resistance of the structure in acidic environments. When dissolved at pH 2, early stage particulates disassemble into a homogeneous population of small oligomers, while the late stage particulates remain unaffected. Particulates at the intermediate stage of maturation partially disassemble into a heterogeneous population of fragments. Importantly, differently matured microparticles show different features when loading a model lipophilic molecule. Our findings suggest conformational transitions localized at the interface as a key step in the maturation of amyloid protein condensates, promoting this phenomenon as an intrinsic knob to tailor the properties of protein microparticles formed via bulk mixing in aqueous solution. This provides a simple and sustainable platform for the design and realization of protein microparticles for tailored applications.

Hyaluronidase-loaded PLGA microparticles as a new strategy for the treatment of pulmonary fibrosis

The aim of this work was to develop an innovative tool for the treatment of pulmonary fibrosis based on our previous findings, which demonstrated that intranasally administered soluble bovine hyaluronidase (HYAL) increases the numbers of mesenchymal (MSC)-like cells in the bronchoalveolar fluid (BALF) and thus reduces the bleomycin-induced fibrosis. To this end, we developed poly(D,L-lactide-co-glycolide) (PLGA) microparticles (MPs) loaded with HYAL (HYAL-MP) to preserve the enzyme's biological activity and to facilitate its delivery to the lung. Nonloaded MPs (Control-MPs) and HYAL-MPs were prepared using the emulsion and solvent evaporation methods and thoroughly characterized. The HYAL-MPs and Control-MPs exhibited an average diameter of 4.3±2.1 and 4.4±1.5 μm, respectively. The encapsulation efficiency of the HYAL-MPs was 68%, and encapsulation led to a reduced release rate. Additionally, the HYAL-MPs were efficiently phagocytosed by J-774.1 cells. Compared with the soluble HYAL, the HYAL-MPs increased the proportion of MSC-like cells in the BALF of C57BL6 mice 96 h after treatment. The efficacy of the HYAL-MPs was also tested in C57BL6 mice that were previously exposed to 4 U/kg of bleomycin to induce lung fibrosis. The results demonstrated that the HYAL-MPs reduced neutrophil recruitment after bleomycin treatment more effectively than did the soluble HYAL, whereas the Control-MPs did not exhibit any effect. The HYAL-MPs also reduced the bleomycin-induced fibrosis more efficiently, and 134% of the collagen deposition in the lung compared with the soluble HYAL and the Control-MPs. In summary, our data indicate that HYAL-MPs are an effective delivery system that could feasibly be used in the treatment of pulmonary fibrosis.

Innovative pharmaceutical development based on unique properties of nanoscale delivery formulation

The advent of nanotechnology has reignited interest in the field of pharmaceutical science for the development of nanomedicine. Nanomedicinal formulations are nanometer-sized carrier materials designed for increasing the drug tissue bioavailability, thereby improving the treatment of systemically applied chemotherapeutic drugs. Nanomedicine is a new approach to deliver the pharmaceuticals through different routes of administration with safer and more effective therapies compared to conventional methods. To date, various kinds of nanomaterials have been developed over the years to make delivery systems more effective for the treatment of various diseases. Even though nanomaterials have significant advantages due to their unique nanoscale properties, there are still significant challenges in the improvement and development of nanoformulations with composites and other materials. Here in this review, we highlight the nanomedicinal formulations aiming to improve the balance between the efficacy and the toxicity of therapeutic interventions through different routes of administration and how to design nanomedicine for safer and more effective ways to improve the treatment quality. We also emphasize the environmental and health prospects of nanomaterials for human health care.

Future of the particle replication in nonwetting templates (PRINT) technology

Particle replication in nonwetting templates (PRINT) is a continuous, roll-to-roll, high-resolution molding technology which allows the design and synthesis of precisely defined micro- and nanoparticles. This technology adapts the lithographic techniques from the microelectronics industry and marries these with the roll-to-roll processes from the photographic film industry to enable researchers to have unprecedented control over particle size, shape, chemical composition, cargo, modulus, and surface properties. In addition, PRINT is a GMP-compliant (GMP=good manufacturing practice) platform amenable for particle fabrication on a large scale. Herein, we describe some of our most recent work involving the PRINT technology for application in the biomedical and material sciences.

Insulin-loaded PLGA/cyclodextrin large porous particles with improved aerosolization properties: in vivo deposition and hypoglycaemic activity after delivery to rat lungs

The aim of the present work is to develop large porous particles (LPP) of poly (lactide-co-glycolide) (PLGA) containing insulin with optimal aerodynamic properties and to test their in vivo potential, in pulmonary delivery. Insulin-loaded LPP were fabricated by a double emulsion method by aid of hydroxypropyl-beta-cyclodextrin (HPbetaCD). Conceiving this system for the controlled release of insulin to the lungs, the aerosolization properties and the release features in simulated lung fluids of PLGA/HPbetaCD/insulin LPP were investigated in depth. The technological results show that the combination of appropriate amounts of insulin and HPbetaCD plays a crucial role to achieve PLGA/HPbetaCD/insulin LPP with the desired bulk and aerodynamic properties, that is a highly porous structure, a very low density (0.1 g/ml), an experimental mass mean aerodynamic diameter (MMAD(exp)) ranging from 4.01 to 7.00 and a fine particle fraction (FPF) estimated to be 26.9-89.6% at the different airflow rates tested (i.e. 30-90 l/min). Confocal microscopy studies, performed after administration of labeled PLGA/HPbetaCD/insulin LPP to the rat lung by means of a low-scale dry powder inhaler (DPI), suggest that particles reach alveoli and remain in situ after delivery. The pharmacological effect of PLGA/HPbetaCD/insulin LPP was confirmed by dose-response studies performed on both normoglycaemic and streptozotocin-induced diabetic rats. While insulin solutions administered via pulmonary route are unable to cause a significant hypoglycaemic effect, insulin delivered through PLGA/HPbetaCD/insulin LPP at the same doses (0.5-4.0 IU/kg) significantly reduces blood glucose level as a function of the administered dose in both animal models. The developed LPP, tested in hyperglycaemic rats at evident pathological conditions, exerts a very significant and longer hypoglycaemic effect even at insulin doses as low as 0.5 IU/kg (about 0.5 mg of PLGA/HPbetaCD/insulin LPP per rat) as compared to a insulin solution. Taken together, our results support the viability of a dry powder formulation based on biodegradable LPP for the controlled release of insulin to the lungs. In vivo data show that PLGA/HPbetaCD/insulin LPP are able to reach alveoli, release insulin, which is absorbed in its bioactive form.