We describe the preparation and characterization of hybrid block copolymer nanoparticles (NPs) for use as multimodal carriers for drugs and imaging agents. Stable, water-soluble, biocompatible poly(ethylene glycol)-block-poly(epsilon-caprolactone) NPs simultaneously co-encapsulating hydrophobic organic actives (beta-carotene) and inorganic imaging nanostructures (Au) are prepared using the flash nanoprecipitation process in a multi-inlet vortex mixer. These composite nanoparticles (CNPs) are produced with tunable sizes between 75 nm and 275 nm, narrow particle size distributions, high encapsulation efficiencies, specified component compositions, and long-term stability. The process is tunable and flexible because it relies on the control of mixing and aggregation timescales. It is anticipated that the technique can be applied to a variety of hydrophobic active compounds, fluorescent dyes, and inorganic nanostructures, yielding CNPs for combined therapy and multimodal imaging applications.

The application of nanoparticles for the delivery and targeting of pharmaceutical, therapeutic and diagnostic agents in cancer therapy has received significant attention in recent years. Nanoparticles may be constructed from a wide range of materials and used to encapsulate or solubilize chemotherapeutic agents for improved delivery in vivo or to provide unique optical, magnetic and electrical properties for imaging and therapy. Several functional nanoparticles have already been demonstrated, including some clinically approved liposome drug formulations and metallic imaging agents. The next generation of nanoparticle-based research is directed at the consolidation of functions into strategically engineered multifunctional systems, which may ultimately facilitate the realization of individual therapy. These multiplexed nanoparticles may be capable of identifying malignant cells by means of molecular detection, visualizing their location in the body by providing enhanced contrast in medical imaging techniques, killing diseased cells with minimal side effects through selective drug targeting, and monitoring treatment in real time. This article highlights recent progress in the design and engineering of multifunctional systems, as well as discusses the development of a new, scalable and economic method for the modular preparation of multiplex nanoparticles where functional properties can be precisely and simply tailored.

There is increased demand for nanoparticles with a high fluorescence yield that have the desired excitation wavelength, surface functionalization, and particle size to act as biological probes. Here, a simple, rapid, and robust method, Flash NanoPrecipitation (FNP), to produce such fluorescent nanoparticles is described. This process involves encapsulation of a hydrophobic fluorophore with an amphiphilic biocompatible diblock copolymer in a kinetically frozen state. FNP is used to produce nanoparticles ranging from 30 to 800 nm with fluorescence emission peaks ranging from, but not limited to, 370 nm to 720 nm. Such fluorescent nanoparticles remain stable in aqueous solutions, and, in contrast to soluble dyes, show no photobleaching. Fluorophores and drugs are incorporated into a single nanoparticle, allowing for simultaneous drug delivery and biological imaging. In addition, functionalization of nanoparticle surfaces with disease‐specific ligands permits precise cell targeting. These features make FNP‐produced fluorescent nanoparticles highly desirable for various biological applications.