Suborgan Level Quantitation of Proteins in Tissues Delivered by Polymeric Nanocarriers.

Amidst the rapid growth of protein therapeutics as a drug class, there is an increased focus on designing systems to effectively deliver proteins to target organs. Quantitative monitoring of protein distributions in tissues is essential for optimal development of delivery systems; however, existing strategies can have limited accuracy, making it difficult to assess suborgan dosing. Here, we describe a quantitative imaging approach that utilizes metal-coded mass tags and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to quantify the suborgan distributions of proteins in tissues that have been delivered by polymeric nanocarriers. Using this approach, we measure nanomole per gram levels of proteins as delivered by guanidinium-functionalized poly(oxanorborneneimide) (PONI) polymers to various tissues, including the alveolar region of the lung. Due to the multiplexing capability of the LA-ICP-MS imaging, we are also able to simultaneously quantify protein and polymer distributions, obtaining valuable information about the relative excretion pathways of the protein cargo and carrier. This imaging approach will facilitate quantitative correlations between nanocarrier properties and protein cargo biodistributions.

Quantitative imaging of the sub-organ distributions of nanomaterials in biological tissues via laser ablation inductively coupled plasma mass spectrometry.

Nanomaterials have been employed in many biomedical applications, and their distributions in biological systems can provide an understanding of their behavior in vivo. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) can be used to determine the distributions of metal-based NMs in biological systems. However, LA-ICP-MS has not commonly been used to quantitatively measure the cell-specific or sub-organ distributions of nanomaterials in tissues. Here, we describe a new platform that uses spiked gelatin standards with control tissues on top to obtain an almost perfect tissue mimic for quantitative imaging purposes. In our approach, gelatin is spiked with both nanomaterial standards and an internal standard to improve quantitation and image quality. The value of the developed approach is illustrated by determining the sub-organ distributions of different metal-based and metal-tagged polymeric nanomaterials in mice organs. The LA-ICP-MS images reveal that the chemical and physical properties of the nanomaterials cause them to distribute in quantitatively different extents in spleens, kidneys, and tumors, providing new insight into the fate of nanomaterials in vivo. Furthermore, we demonstrate that this approach enables quantitative co-localization of nanomaterials and their cargo. We envision this method being a valuable tool in the development of nanomaterial drug delivery systems.

Synergistic Treatment of Multidrug-Resistant Bacterial Biofilms Using Silver Nanoclusters Incorporated into Biodegradable Nanoemulsions.

Multidrug resistance (MDR) in bacteria is a critical global health challenge that is exacerbated by the ability of bacteria to form biofilms. We report a combination therapy for biofilm infections that integrates silver nanoclusters (AgNCs) into polymeric biodegradable nanoemulsions (BNEs) incorporating eugenol. These Ag-BNEs demonstrated synergistic antimicrobial activity between the AgNCs and the BNEs. Microscopy studies demonstrated that Ag-BNEs penetrated the dense biofilm matrix and effectively disrupted the bacterial membrane. The Ag-BNE vehicle also resulted in more effective silver delivery into the biofilm than AgNCs alone. This combinacional system featured disruptionof biofilms by BNEs and enhanced delivery of AgNCs for synergy to provide highly efficient killing of MDR biofilms.