Table 2.

Tumor-on-chip models incorporating patient-derived samples for therapy testing.

Year	Sample Type	Cell Culture	Microfluidic Device	Application	Analysis	Main Outcomes	Ref.
	Chemotherapy
2015	Primary human lung tumors and squamous carcinoma tissues	Dissociated cells from tissues; monocultured or co-cultured	Two PDMS parts consisting of microwells, fabricated by stereolithography epoxy molds, plasma-bonded	Drug treatment with cisplatin for 48 h	On-chip: Live–dead staining and fluorescence imaging to assess cell viability Off-chip: Flow cytometry for cell sorting, followed by caspase-3/7 activity of the supernatant to assess apoptosis	System efficiency was high with little cell loss in the microfluidic network. Primary pericytes (PCs) had a protective effect on the primary epithelial lung tumor cells (PLETCs) from the damaging effects of the chemotherapeutical drug.	[93]
2016	Primary human ovarian cancer tissues and prostate cancer tissues	Microdissected cylindrical tissues	Two PDMS replicas with 5 open channels containing 5 microwells, fabricated by micromachined PMMA master molds, plasma-bonded	Drug treatment with carboplatin for 48 h	On-chip: Fluorescence staining and imaging of live tissues to assess cell viability Off-chip: Endpoint flow cytometry analysis to assess the survival of individual cells within the microtissues	The microfluidic platform was operated using simple instruments typically found in cell biology laboratories. Drug treatment response measured in the microfluidic chip was concordant with the clinical response of the patient.	[94]
2017	Primary human nasopharyngeal tumor tissues	Dissociated cells from tissues; 100–200 cells per droplet	PDMS microchannels containing 48 droplet formation wells, fabricated by a SU-8-patterned silicon wafer molds, plasma-bonded to glass coverslips	Drug treatment with bortezomib and cisplatin for 16–24 h	On-chip: Ethidium homodimer 1 labeling during cell seeding, brightfield and red fluorescence imaging to assess cell number and viability	The microfluidic system was capable of drug-screening as few as 16,000 cells obtained from primary cancer within 24 h after tumor resection from patients.	[95]
2018	Primary human mesothelioma tumor tissues	Dissociated cells from tissues mixed with hyaluronic acid and hydrogel precursor; 20 million cells/mL were seeded	Six chambers produced in an aluminum foil–adhesive film using a cutting plotter, attached to a glass slide (bottom) and polystyrene slide (top)	Drug treatment with carboplatin–pemetrexed or cisplatin–pemetrexed for 7 d	On-chip: Live–dead staining and fluorescence imaging to assess cell viability, proliferation assays, visualization of biomarkers using IHC *	The microfluidic platform was capable of maintaining the cell viability over 14 d and key mesothelioma biomarkers in patient-derived organoids (accurate tumor phenotype). Drug response of organoids was concordant with clinical outcomes. Patient-to-patient tumor heterogeneity was demonstrated.	[90]
2018	Primary human prostate cancer biopsies	Biopsies were minced, passaged and injected into the device; 24,000 cells were seeded	Two PDMS parts containing 240 square microwells fabricated by SU-8-patterned silicon wafer molds, plasma-bonded	Drug treatment with cisplatin, docetaxel and enzalutamide for 12 h	On-chip: Live–dead staining and fluorescence imaging to assess cell viability, calcein assay to assess concentration gradient formation Off-chip: RT-qPCR to assess prostate cancer cell gene expression	Proof of concept study. The microfluidic platform was capable of forming concentration gradient and maintain its stability for 12–16 h.	[96]
2018	Primary human triple-negative breast cancer tumor biopsy	1×105 cells/mL were seeded; ~300 spheroids on the device	Two PDMS plasma-bonded layers with pillar array fabricated by two printed transparent film masks	Drug treatment with doxorubicin or docetaxel for 72 h	On chip: Live–dead staining assay, fluorescence imaging to assess spheroid number and size Off-chip: qRT-PCR to assess cancer stem cell marker expression	Proof of concept study. The microfluidic platform was capable of controlling the spheroid size. Spheroids showed a similar differential drug response observed in the patient.	[78]
2018	Primary human triple-negative breast cancer tumor tissue biopsies	Patient-derived tumor organoids (PDTO) from sectioned tissues; 1×107 cells/mL cell suspension with Matrigel	PDMS device with 8 tumor tissue chambers fabricated by SU-8-patterned silicon wafer molds, plasma-bonded to a flat PDMS sheet	Drug treatment with paclitaxel for 48 h	On-chip: Immunostaining and fluorescence imaging to assess tumor growth, fluorescently tagged dextran perfusion via device to assess vessel permeability assessment	Proof of concept study. The microfluidic platform was capable of maintaining the viability of the primary tissue for up to 21 d. A tumor-on-a-chip device that mimics biological mass transport was designed, where 3D microvascular network was created prior to loading PDTO.	[97]
2018	Primary human glioblastoma tumor tissues	Dissociated cells from tissues; 0.5×106 cells/mL were seeded	Poly-(ethylene glycol) diacrylate (PEGDA) hydrogel layer consisting of 7 channels with 9–11 microwells per channel, fabricated by printed plastic photomasks, crosslinked between two cover glass slides	Drug treatment with combination of bevacizumab and temozolomidefor 7 d	On-chip: Immunostaining and fluorescence imaging to assess spheroid formation Off-chip: Trypan blue staining to assess cell viability	Proof of concept study. Patient-to-patient tumor heterogeneity was demonstrated.	[88]
2019	Primary human small-cell lung cancer (SCLC) biopsies	Mechanically dissociated lung cancer organoids (LCOs) mixed with Matrigel	PDMS device consisting of 29 microwells fabricated by SU-8-patterned silicon wafer molds, plasma-bonded to a cover glass	Drug treatment with cisplatin and etoposide for 72 h	On-chip: Fluorescence imaging to assess organoid size, end point live–dead staining and fluorescence imaging to assess cell viability, apoptosis analysis Off-chip: Genomic analysis to evaluate the somatic mutations, qRT-PCR to characterize the specific marker expressions for cancer stem cells	First demonstration of 3D lung cancer organoid production from small-cell lung cancer tumors. The microfluidic device was capable of culturing these organoids, as well as performing drug sensitivity tests. The centers of the organoids could survive chemotherapy-induced cell death, which may help to elucidate chemotherapy resistance mechanisms.	[89]
2020	Primary metastatic human rectal tumor tissues	Tissue slices	PMMA plate consisting of 40 wells with an integrated channel network layer, fabricated by CO2 laser micromachining, sealed with chloroform vapor	Drug treatment with combinations of FOLFOX, FOLFIRI ** and staurosporine for 48 h	Off-chip: Proliferation assay and live–dead staining to assess cell viability, fluorescence imaging to assess cell death	The microfluidic device was capable of delivering multiplexed anti-cancer drugs on tumor slices and was compatible with on-chip live–dead staining.	[21]
2020	Primary human pancreatic ductal adenocarcinoma tumor organoid	Organoids were suspended in single cells and cultured in Matrigel with human dermal fibroblasts, before introducing this suspension (6800–13,600 cells) in HUVEC (75,000–12,5000 cells) scaffold	Two PDMS molds fabricated by SU-8-patterned silicon wafer molds, between PDMS molds and a PDMS sheet, pressed and perfused with a highly elastic polyester material, plasma-bonded to a silicon wafer	Drug treatment with gemcitabine for 96 h	On-chip: Luminescence assay to assess cell viability, fluorescence imaging to assess organoid size and morphology	Tumor-derived cells cultured in the microfluidic system only underwent ECM remodeling when co-cultured with fibroblasts. These changes, as well as vascularization, decreased the efficacy of gemcitabine treatment.	[98]
	Radiotherapy
2019	Primary human head and neck squamous cell carcinoma tumor tissue	Tumor slices	Two PEEK plate parts consisting of 1 well for 1 sample, reversibly sealed by screws	Irradiation with a photon beam; 10 Gy in 5 × 2 Gy fractions in a 72 h schema; drug treatment with cisplatin for final 48 h alongside the 5 × 2 Gy irradiation fractions	Off-chip: Trypan blue/PI staining to assess tissue viability, flow cytometry to assess cell death, IHC * staining to assess radiation response markers	The microfluidic system was capable of maintaining the viability of precision-cut tumor slices for 68 h. This system enabled monitoring of the effects of irradiation and chemoradiation on tumor slices.	[15]
	Immunotherapy
2018	Primary human non-small-cell lung cancer biopsies	Tumor fragments	Cyclic olefin copolymer (COC) device consisting of chevron-like 12-lane channel pattern, fabricated by micromachined aluminum master mold, bonded to a COC film using a heated lamination process	Treatment with an anti-PD-1 antibody pretreated tumor-infiltrating lymphocytes (TILs), monitored daily for 7–10 d	On-chip: Fluorescence staining and imaging to assess cell growth and viability Off-chip: Magnetic cell sorting using flow cytometry to separate tumor cells	The microfluidic system was capable of studying interactions between autologous lymphocytes and biopsy sample in response to an anti-PD-1 antibody. The sample showed responder behavior, mimicking the in vivo tumor response.	[72]
2018	Primary human metastatic melanoma tumor tissues	Minced tumor tissues mixed with collagen	Cyclic olefin polymer device by AIM BIOTECH consisting of 3 chambers	Treatment with anti-PD-1 (pembrolizumab, 250 μg/mL), anti-CTLA-4 (ipilimumab, 50 μg/mL) or combination for 5–9 d	Oh-chip: Live–dead staining and fluorescence imaging to assess cell viability Off-chip: Flow cytometry for immune profiling, RNA-seq, cytokine profiling in media	The microfluidic system was capable of performing a range of on-/off-chip analyses. It demonstrated the immune checkpoint sensitivity of patient-derived tumor spheroids, which is not seen in 2D cultures.	[92]
2019	Primary human non-small-cell lung carcinoma tumor biopsies	Tumor fragments	Pro3dure GR-10 resin device fabricated by digital light projection stereolithography (DLP-SLA) 3D printing	Treatment with anti-PD-1 antibodies, monitored after 24, 48 and 72 h	On-chip: Live–dead staining and fluorescence imaging to assess cell viability, resident lymphocyte response to selected antibodies Off-chip: Fluorescence imaging to determine healthy tumor fragments	The microfluidic system was capable of culturing biopsied tumor tissue and resident lymphocytes in a dynamic perfusion system. It enabled the monitoring of tumor response to immunotherapeutic agents. Clinical correlation of the laboratory results is needed to determine its utility in guiding personalized medicine approaches.	[17]
	Combined therapy
2018	Primary human pancreatic tumor biopsies	Dissociated cells from tumors; ~100 cells encapsulated in each plug	Droplet-based PDMS device consisting of 1140 plugs, fabricated by AZ-40XT patterned silicon wafer molds, plasma-bonded to a thin elastic PDMS membrane with integrated Braille valves	Drug treatment with chemotherapeutic drugs (oxaliplatin and gemcitabine), specific kinase targets (Cyt387, PHT-427, MK-2206, GDC0941, gefitinib, ACHP, AZD6244) and one cytokine (tumor necrosis factor-α) for up to 14 d	On-chip: Fluorescence staining and imaging to assess cell viability, caspase-3 activity to access cell apoptosis	The microfluidic system was capable of screening 62 different drug conditions on biopsy-derived cells. No drug combination had strong efficacy across all patient samples, encouraging the consideration of personalized medicine approaches to pancreatic cancer	[14]

* IHC = immunohistochemistry staining; ** FOLFOX = 5-FU and Oxaliplatin; FOLFIRI = 5-FU and Irinotecan.