Formation of Polymeric Hollow Microcapsules and Microlenses Using Gas-in-Organic-in-Water Droplets

Continuous synthesis of BaFe2O4 and BaFe12O19 nanoparticles in a droplet microreactor for efficient detection of antihistamine drugs in oral fluid using surface-assisted laser desorption/ionization mass spectrometry

Surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) has received considerable attention as a complementary approach to matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), offering substantial potential for analyzing molecules in the low-mass region. Herein, we propose a facile method, a microreactor for the synthesis of two types of barium ferrite (BaFe2O4 and BaFe12O19) nanoparticles (NPs) within moving droplets for detecting antihistamine (AH) drugs in oral fluid (OF). The synthesized BaFe2O4 and BaFe12O19 NPs exhibited small particle size, good ultraviolet absorption, and excellent performance in SALDI-MS, as determined by survival yield measurements. The limits-of-detection for AH drugs were in the range of 1 pg mL-1 to 100 ng mL-1, and spot-spot reproducibility of the SALDI substrates was satisfactory. Moreover, when analyzing cetirizine in OF, the obtained recoveries of cetirizine were 101% and 99% using BaFe2O4 and BaFe12O19 NP, respectively. Furthermore, the proposed method was validated by analyzing OF samples from a healthy volunteer who consumed a 5 mg levocetirizine tablet for seven days. SALDI-MS analysis confirmed the successful detection of endogenous components, the parent ion of cetirizine, and other exogenous substances. This study reports an advanced application of droplet microreactor technology for designing and synthesizing a wide range of novel and efficient SALDI-MS substrates for various applications.

Recent Progress of Droplet Microfluidic Emulsification Based Synthesis of Functional Microparticles

The remarkable control function over the functional material formation process enabled by droplet microfluidic emulsification approaches can lead to the efficient and one-step encapsulation of active substances in microparticles, with the microparticle characteristics well regulated. In comparison to the conventional fabrication methods, droplet microfluidic technology can not only construct microparticles with various shapes, but also provide excellent templates, which enrich and expand the application fields of microparticles. For instance, intersection with disciplines in pharmacy, life sciences, and others, modifying the structure of microspheres and appending functional materials can be completed in the preparation of microparticles. The as-prepared polymer particles have great potential in a wide range of applications for chemical analysis, heavy metal adsorption, and detection. This review systematically introduces the devices and basic principles of particle preparation using droplet microfluidic technology and discusses the research of functional microparticle formation with high monodispersity, involving a plethora of types including spherical, nonspherical, and Janus type, as well as core-shell, hole-shell, and controllable multicompartment particles. Moreover, this review paper also exhibits a critical analysis of the current status and existing challenges, and outlook of the future development in the emerging fields has been discussed.

Functional microspheres for tissue regeneration

As a new type of injectable biomaterials, functional microspheres have attracted increasing attention in tissue regeneration because they possess some advantageous properties compared to other biomaterials, including hydrogels. A variety of bio-inspired microspheres with unique structures and properties have been developed as cellular carriers and drug delivery vehicles in recent years. In this review, we provide a comprehensive summary of the progress of functional and biodegradable microspheres that have been used for tissue regeneration over the last two decades. First, we briefly introduce the biomaterials and general methods for microsphere fabrication. Next, we focus on the newly developed technologies for preparing functional microspheres, including macroporous microspheres, nanofibrous microspheres, hollow microspheres, core-shell structured microspheres, and surface-modified functional microspheres. After that, we discuss the application of functional microspheres for tissue regeneration, specifically for bone, cartilage, dental, neural, cardiac, and skin tissue regeneration. Last, we present our perspectives and future directions of functional microspheres as injectable carriers for the future advancement of tissue regeneration.

Microfluidics for core-shell drug carrier particles - a review

Core-shell drug-carrier particles are known for their unique features. Due to the combination of superior properties not exhibited by the individual components, core-shell particles have gained a lot of interest. The structures could integrate core and shell characteristics and properties. These particles were designed for controlled drug release in the desired location. Therefore, the side effects would be minimized. So, these particles' advantages have led to the introduction of new methods and ideas for their fabrication. In the past few years, the generation of drug carrier core-shell particles in microfluidic chips has attracted much attention. This method makes it possible to produce particles at nanometer and micrometer levels of the same shape and size; it usually costs less than other methods. The other advantages of using microfluidic techniques compared to conventional bulk methods are integration capability, reproducibility, and higher efficiency. These advantages have created a positive outlook on this approach. This review gives an overview of the various fluidic concepts that are used to generate microparticles or nanoparticles. Also, an overview of traditional and more recent microfluidic devices and their design and structure for the generation of core-shell particles is given. The unique benefits of the microfluidic technique for core-shell drug carrier particle generation are demonstrated.

Preparation of Poly(ionic liquid) Hollow Particles with Switchable Permeability

Poly(ionic liquid) (PIL) particles with a single-hollow structure are prepared by suspension polymerization from monomer droplets consisting of the hydrophobic ionic liquid monomer [2-(methacryloyloxy)ethyl]trimethylammonium bis(trifluoromethanesulfonyl)amide, ethylene glycol dimethacrylate, and n-butyl acetate containing dissolved poly(n-butyl methacrylate). The obtained PIL hollow particles' shells can be changed from hydrophobic to hydrophilic by anion exchange using a LiBr/ethanol solution. In the case of hydrophilic PIL hollow particles, the water-soluble fluorescent materials can penetrate into the hollow structure, whereas in the case of hydrophobic PIL hollow particles, penetration of the fluorescent materials is restricted. In addition, the encapsulated water-soluble materials can be preserved into the hollow part by changing the shell property of the PIL particle encapsulated with the water-soluble materials from hydrophilic to hydrophobic.