Inorganic nanoparticles (NPs) are promising drug delivery carriers owing to their high drug loading efficiency, scalable preparation, facile functionalization, and chemical/thermal stability. However, the clinical translation of inorganic nanocarriers is often hindered by their poor biodegradability and lack of controlled pH response. Herein, a fully degradable and pH-responsive DOX@ACC/PAA NP (pH 7.4-5.6) is developed by encapsulating doxorubicin (DOX) in poly(acrylic acid) (PAA) stabilized amorphous calcium carbonate (ACC) NPs. The DOX-loaded NPs have small sizes (62 ± 10 nm), good serum stability, high drug encapsulation efficiency (>80%), and loading capacity (>9%). By doping proper amounts of Sr 2+ or Mg 2+ , the drug release of NPs can be further modulated to higher pH responsive ranges (pH 7.7-6.0), which enables drug delivery to the specific cell domains of tissues with a less acidic microenvironment. Tumor inhibition and lower drug acute toxicity are further confirmed via intracellular uptake tests and zebrafish models, and the particles also improve pharmacokinetics and drug accumulation in mouse xenograft tumors, leading to enhanced suppression of tumor growth. Owing to the excellent biocompatibility, biodegradability, and tunable drug release behavior, the present hybrid nanocarrier may find broad applications in tumor therapy.

Flexibility, diversity, and applicability in complicated situations are urgently required for next generation of tough hydrogels with good processability. To achieve this good performance, complicated chemical polymerization is conventionally involved in the preparation of tough hydrogels, which is tedious, energy-consuming, detrimental to the environment, and hard to scale up. In contrast, physically cross-linking primarily the electrostatic force is always adopted as complementary to chemical cross-linking. Here we propose a simple, nonpolymerization method to develop a novel type of dual physically cross-linked tough hydrogel, which consists of poly­(vinyl alcohol) (PVA) crystallite cross-linked network, and hyaluronic acid–Fe3+ physically cross-linked network. Instead of using electrostatic interaction, nanosized PVA crystallites were chosen as major cross-linking sites for the primary network of the hydrogel. By annealing the freeze–thaw hydrogel followed by the Fe3+-carboxylic group complexation to construct the second network, extraordinary mechanical performance including excellent tensile strength (∼8 MPa), remarkable toughness (∼19.6 MJ/m3) and high elastic modulus (∼10 MPa) was successfully achieved. Especially, the precursor solution with viscoelastic properties was demonstrated to as a “new” type of ink for three-dimensional (3D) printing with no UV curing is required. Such design provides a simple and new avenue for the preparation of tough hydrogels featured with 3D printing processability and we believe that the design can be potentially applied for building future soft devices.

Photothermal‐chemotherapeutic nanoparticles (NPs) are attracting increasing attention and becoming more widely used for cancer therapy in the clinic due to their noninvasiveness, notable tissue penetration abilities, and low systemic adverse effects. However, functional ligands are conventionally modified onto photothermal NPs to well stabilize the inorganic particles suffering from complex chemical modifications, low productivity, and batch‐to‐batch inconsistencies, and thus significantly restricting their clinical applications. Herein, flash nanoprecipitation (FNP) is taken advantage of to afford rapid and uniform mixing for generating local supersaturated CuS clusters for small and highly stable CuS NPs effectively stabilized by polyacrylic acid through a continuous strategy. It greatly reduces the complexity for CuS NPs synthesis and functionalization in a facile intensified mixing process. These as‐synthesized particles are high‐drug loading, scalable, and most importantly, it is easy to control their sizes and charges through external conditions. Toxicity and tumor inhibition experiments confirm the high cell toxicity and good suppression of tumor growth under near‐infrared irradiation indicating a promising prospect of FNP in the large‐scale and continuous yielding of highly stable and high‐performing photothermal‐chemotherapeutic NPs for cancer therapy.

No abstract

As an important precursor of crystalline phases, amorphous calcium carbonate (ACC), especially ultrasmall ACC clusters, have been attracting great interest in fundamental research, materials chemistry, as well as industrial applications. However, it is still challenging to synthesize stable ACC clusters in water that can be isolated and concentrated without severe aggregation. Herein, we report a facile dialysis method for producing colloidally stable ACC clusters that are well dispersed in water with the protection of specific polycarboxylic acids, which could be also easily deprotected by small-molecule acids like sodium citrate. Inherent proto-calcite short-range order is found to be present in all the obtained ACC clusters. The present strategy not only allows for the preparation of monodisperse isolated ACC clusters in aqueous solution but also shows great potential in industrial uses like waste water treatment.