SUMMARY In vitro cancer cultures, including 3-dimensional organoids, typically contain exclusively neoplastic epithelium but require artificial reconstitution to recapitulate the tumor microenvironment (TME). The co-culture of primary tumor epithelia with endogenous, syngeneic tumor-infiltrating lymphocytes (TILs) as a cohesive unit has been particularly elusive. Here, an air-liquid interface (ALI) method propagated Patient-Derived Organoids (PDOs) from >100 human biopsies or mouse tumors in syngeneic immunocompetent hosts as tumor epithelia with native embedded immune cells (T, B, NK, macrophages). Robust droplet-based, single cell simultaneous determination of gene expression and immune repertoire indicated that PDO TILs accurately preserved the original tumor T cell receptor (TCR) spectrum. Crucially, human and murine PDOs successfully modeled immune checkpoint blockade (ICB) with anti-PD-1- and/or anti-PD-L1 expanding and activating tumor antigen-specific TILs and eliciting tumor cytotoxicity. Organoid-based propagation of primary tumor epithelium en bloc with endogenous immune stroma should enable immunooncology investigations within the TME and facilitate personalized immunotherapy testing.

Summary Nociceptor sensory neurons are specialized to detect potentially damaging stimuli, protecting the organism by initiating the sensation of pain and eliciting defensive behaviors. Bacterial infections produce pain by unknown molecular mechanisms, although they are presumed secondary to immune activation. Here we demonstrate that bacteria directly activate nociceptors, and that the immune response mediated through TLR2, MyD88, T cells, B cells, and neutrophils/monocytes is not necessary for Staphylococcus aureus induced pain in mice. Mechanical and thermal hyperalgesia parallels live bacterial load rather than tissue swelling or immune activation. Bacteria induce calcium flux and action potentials in nociceptor neurons, in part via bacterial N-formylated peptides and the pore-forming toxin alpha-hemolysin through distinct mechanisms. Specific ablation of Nav1.8-lineage neurons, which include nociceptors, abrogated pain during bacterial infection, but concurrently increased local immune infiltration and lymphadenopathy of the draining lymph node. Thus, bacterial pathogens produce pain by directly activating sensory neurons that modulate inflammation, an unsuspected role for the nervous system in host-pathogen interactions.

This tutorial review aims to introduce a new kind of biomaterials-molecular hydrogels of therapeutic agents. Based on the molecular self-assembly in water, it is possible to transform therapeutic agents into analogues that form hydrogels without compromising their pharmacological efficacy. This transformation can be beneficial in three aspects: (i) the therapeutic agents become "self-deliverable" in the form of hydrogels; (ii) the self-assembly of hydrogelators of drugs might confer new and useful properties such as multivalency or high local densities; (iii) the exploration of molecular hydrogels of drugs may ultimately lead to bioactive molecules that have dual or multiple roles. By summarizing the reports on the molecular hydrogels made from clinical used drugs or other bioactive molecules, this article presents representative molecular hydrogels of therapeutics and outlines the promises and challenges for developing this new class of biomaterials.

We report a new type of multifunctional nanomaterials, FePt@Fe2O3 yolk-shell nanoparticles, that exhibit high cytotoxicity originated from the FePt yolks and strong MR contrast enhancement resulting from the Fe2O3 shells. Encouraged by the recently observed high cytotoxicity of FePt@CoS2 yolk-shell nanoparticles, we used Fe2O3 to replace CoS2 as the shells to further explore the applications of the yolk-shell nanostructures. The ultralow IC50 value (238 +/- 9 ng of Pt/mL) of FePt@Fe2O3 yolk-shell nanoparticles likely originates from the fact that the slow oxidation and release of FePt yolks increases the cytotoxicity. Moreover, compared with two commercial magnetic resonance imaging (MRI) contrast agents, MION and Sinerem, the FePt@Fe2O3 yolk-shell nanoparticle showed stronger contrast enhancement according to their apparent transverse relaxivity values (r2* = 3.462 (microg/mL)(-1) s(-1)). The bifunctional FePt@Fe2O3 yolk-shell nanoparticles may serve both as an MRI contrast agent and as a potent anticancer drug. This work indicates that these unique yolk-shell nanoparticles may ultimately lead to new designs of multifunctional nanostructures for nanomedicine.

In the rapidly developing areas of nanobiotechnology, magnetic nanoparticles (MNPs) are one type of the most well-established nanomaterials because of their biocompatibility and the potential applications as alternative contrast enhancing agents for magnetic resonance imaging (MRI). While the development of MNPs as alternative contrast agents for MRI application has moved quickly to testing in animal models and clinical trials, other applications of biofunctional MNPs have been explored extensively at the stage of qualitative or conceptual demonstration. In this critical review, we summarize the development of two straightforward applications of biofunctional MNPs--manipulating proteins and manipulating cells--in the last five years or so and hope to provide a relatively comprehensive assessment that may help the future developments. Specifically, we start with the examination of the strategy for the surface functionalization of MNPs because the applications of MNPs essentially depend on the molecular interactions between the functional molecules on the MNPs and the intended biological targets. Then, we discuss the use of MNPs for manipulating proteins since protein interactions are critical for biological functions. Afterwards, we evaluate the development of the use of MNPs to manipulate cells because the response of MNPs to a magnetic field offers a unique way to modulate cellular behavior in a non-contact or "remote" mode (i.e. the magnet exerts force on the cells without direct contact). Finally, we provide a perspective on the future directions and challenges in the development of MNPs for these two applications. By reviewing the examples of the design and applications of biofunctional MNPs, we hope that this article will provide a reference point for the future development of MNPs that address the present challenges and lead to new opportunities in nanomedicine and nanobiotechnology (137 references).

Enzymes, together with the process of self-assembly, constitute necessary components of the foundation of life on the nanometre scale. The exceedingly high efficiency and selectivity exhibited by enzymes for catalyzing biotransformations naturally lead to the exploration of enzyme mimics and the applications of enzymes in industrial biotransformations. While the mimicking of enzymes aims to preserve the essence of enzymes in a simpler system than proteins, industrial biotransformations demand high activity and stability of enzymes. Recent research suggests that small peptide-based nanofibers in the form of molecular hydrogels can provide a general platform to achieve both important goals. This tutorial review will introduce the recent progress of these research activities on small peptide-based nanomaterials for catalysis and hopes to provide a starting point for further explorations that ultimately may lead to practical applications of enzymes and enzyme mimics for addressing important societal problems in energy, environment, and health.

sequencing data. J.O. and S.H. provided newly diagnosed MS patient PBMCs. J.I. generated BMDCs. V.B.M. performed histopathology and analyzed uveitis data. X.J. assisted in sequencing TCRs and RNA-seq. L.M.S. guided and M.J.S. analyzed RNAseq data. K.C.G. and R.A.F. guided experiments involving mouse yeast-pMHC display and R.A.F. analyzed yeast-peptide MHC sequencing data. Y.C. guided experiments involving γδ TCR sequencing and analysis. N.S. and M.M.D. wrote the manuscript with input from all the authors.Data availability RNA-seq data and Yeast p-MHC selection data are deposited to the Gene Expression Omnibus (GEO) data repository with accession number GSE130975. Source data for each figure are provided. Other data that support the findings of this study are available from the corresponding author upon reasonable request.

Reactive oxygen species (ROS) are crucial molecules in cancer therapy. Unfortunately, the therapeutic efficiency of ROS is unsatisfactory in clinic, primarily due to their rigorous production conditions. By taking advantage of the intrinsic acidity and overproduction of H 2 O 2 in the tumor environment, we have reported an ROS nanoreactor based on core−shell-structured iron carbide (Fe 5 C 2 @Fe 3 O 4 ) nanoparticles (NPs) through the catalysis of the Fenton reaction. These NPs are able to release ferrous ions in acidic environments to disproportionate H 2 O 2 into • OH radicals, which effectively inhibits the proliferation of tumor cells both in vitro and in vivo. The high magnetization of Fe 5 C 2 @Fe 3 O 4 NPs is favorable for both magnetic targeting and T 2 -weighted magnetic resonance imaging (MRI). Ionization of these NPs simultaneously decreases the T 2 signal and enhances the T 1 signal in MRI, and this T 2 /T 1 switching process provides the visualization of ferrous ions release and ROS generation for the supervision of tumor curing. These Fe 5 C 2 @Fe 3 O 4 NPs show great potential in endogenous environment-excited cancer therapy with high efficiency and tumor specificity and can be guided further by MRI.