Spatiotemporal delivery system embedded in 3d-printing

Abstract

Provided herein is a 3D printing system and related compositions, and method of using such, that can produce a polymeric microfiber having embedded microspheres encapsulating an active agent with micron precision and high spatial and temporal resolution.

1 . A method of forming a biocompatible scaffold, the method comprising:
 (i) encapsulating at least one agent in a plurality of microspheres;   (ii) combining the plurality of microspheres and a matrix material, the matrix material being suitable for forming a scaffold via 3D printing;   (iii) introducing the combination of microspheres and matrix material into a first cartridge of a 3D printing device;   (iv) heating the combination of microspheres and matrix material in the first cartridge sufficiently to allow dispensing of the combination while preventing substantial degradation of the microsphere or the at least one agent encapsulated in the microsphere;   (v) dispensing the heated combination of microspheres and matrix material from the first cartridge through a printing needle to form a polymeric microfiber, wherein the microspheres are distributed through the polymeric microfiber; and   (vi) forming a scaffold comprising a plurality of the polymeric microfibers, wherein the microspheres are distributed through the scaffold by way of the polymeric microfibers.   
     
     
         2 . (canceled) 
     
     
         3 . (canceled) 
     
     
         4 . The method of  claim 1 , wherein
 the microspheres comprise at least a first group of microspheres and a second group of microspheres;   the first group of microspheres and the second group of microspheres comprise at least one agent; and   the first group of microspheres and the second group of microspheres comprise at least one different agent.   
     
     
         5 . The method of further comprising introducing the combination of microspheres and matrix material into a second cartridge of a 3D printing device;
 heating the combination of microspheres and matrix material in the second cartridge sufficiently to allow dispensing of the combination of microspheres and matrix material while preventing substantial degradation of the microsphere or the agent encapsulated in the microsphere; and   interchanging the first cartridge and the second cartridge during a printing process.   
     
     
         6 . The method or composition of  claim 1 , wherein the at least one agent comprises a growth factor. 
     
     
         7 . The method of  claim 1  further comprising stem cells, wherein the growth factor stimulates fibroblastic, chondrogenic, or osteogenic differentiation of the stem cells. 
     
     
         8 . The method of  claim 6 , wherein a first growth factor and a second growth factor are alternately embedded in the microfibers. 
     
     
         9 . The method of  claim 1 , wherein the at least one agent comprises a growth factor selected from the group consisting of CTGF, TGFβ, TGFβ3, CTGF, BMPs, SDF, bFGF, IGF, GDF, PDGF, VEGF, or EGF, or an isoform thereof. 
     
     
         10 . The method of  claim 1 , wherein the matrix material comprises polycaprolactone (PCL) and the polymeric microfiber comprises PCL. 
     
     
         11 . The method of  claim 1 , wherein the combination of microspheres and matrix material are heated to less than the melting point of the microsphere. 
     
     
         12 . The method of  claim 1 , wherein the combination of microspheres and matrix material are heated to about 60° C., about 65° C., about 70° C., about 75° C., about 80° C., about 85° C., about 90° C., about 95° C., about 100° C., about 105° C., about 110° C., about 120° C., about 130° C., about 140° C., about 150° C., about 160° C., about 170° C., about 180° C., or about 190° C. 
     
     
         13 . The method of  claim 1 , wherein bioactivity of an encapsulated growth factors is substantially maintained. 
     
     
         14 . The method of  claim 1 , wherein the printing needle has an inner diameter of about 20 μm to about 750 μm. 
     
     
         15 . The method of  claim 1 , wherein the printing needle has an inner diameter of about 50 μm to about 400 μm. 
     
     
         16 . The method of  claim 1 , wherein the 3D printed scaffold comprises microstrands having a microstrand diameter of about 100 μm to about 400 μm. 
     
     
         17 . The method of  claim 1 , wherein the 3D printed scaffold comprises microstrands having an inter-microstrand spacing or microchannel width of about 100 μm to about 600 μm. 
     
     
         18 . The method of  claim 1 , wherein a growth factor encapsulated microsphere (μS)
 (i) has a diameter of about 10 μm to about 600 μm; 
 (ii) is embedded at about 10 mg to about 100 mg μS per about 1 g of matrix material; 
 (iii) has sustained release of growth factor for at least 42 days; or 
 (iv) is about 50 mg μS per 1 g matrix material. 
 
     
     
         19 . The method of  claim 1 , wherein the scaffold, composition, or polymeric fiber is treated with NaOH to create micro-pores. 
     
     
         20 . The method of  claim 1 , wherein the method or composition results in the formation of a multi-tissue complex and the mechanical properties or composition of the resulting regenerated multi-tissue complex have substantially similar mechanical properties or composition of a corresponding native multi-tissue complex. 
     
     
         21 . The method of  claim 1 , further comprising dispensing a plurality of heated matrix materials or a plurality of combinations heated matrix materials or microspheres from a plurality of cartridges, the contents of each cartridge independently selected. 
     
     
         22 . The method of  claim 21 , wherein each cartridge of the plurality of cartridges (i) comprises a printing needle or a heating element or (ii) shares a printing needle or a heating element, or (iii) a combination thereof. 
     
     
         23 . The method of  claim 21 , wherein the plurality of cartridges comprises one or more active cartridges dispensing matrix material, microspheres, or a combination thereof. 
     
     
         24 . The method of  claim 23 , wherein the one or more active cartridges can be switched among the plurality of cartridges before, during, or after dispensing the heated combination. 
     
     
         25 . The method of  claim 1 , wherein heating temperature is about the melting temperature of the matrix material and the combination of the matrix material and microencapsulated active agent is heated such that 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, or 10% of the total volume of microspheres do not reach more than 60° C. for more than about 10-40 minutes. 
     
     
         26 . The method  claim 25 , wherein the combination of the matrix material and microencapsulated active agent is heated such that 80% of the total volume of microspheres do not reach more than 45° C. for more than about 30 minutes. 
     
     
         27 . The method of  claim 21 , wherein a first printing cartridge comprising the combination of the matrix material and microencapsulated active agent is switched for a second printing cartridge comprising the combination of the matrix material and microencapsulated active agent before 80% of the total volume of microspheres do reach more than 45° C. for more than about 30 minutes. 
     
     
         28 . A method of treating a tissue defect with the scaffold produced according to  claim 1 , comprising:
 implanting the scaffold into a subject in need thereof.   
     
     
         29 . The method of  claim 28 , wherein the tissue defect is associated with a multi-tissue interface selected from the group consisting of musculoskeletal system; craniofacial system; periodontium; cementum (CM)-periodontal ligament (PDL)-alveolar bone (AB) complex; ligament-to-bone insertion; tendon-to-bone insertion; rotator cuff; supraspinatus tendon-to-bone interface; interface between tendon, fibrocartilage, or bone; supraspinatus tendon-fibrocartilage-bone interface; articular cartilage-to-bone junction; anterior cruciate ligament (ACL)-to-bone complex; anterior cruciate ligament-fibrocartilage-bone interface; intervertebral disc; nucleus pulposus-annulus fibrosus-endplates; cementum-periodontal ligament-alveolar bone; muscle-to-tendon; inhomogeneous or anisotropic tissues; knee meniscus; temporomandibular joint disc; periodontium; root-periodontium complex; synovial joints; or fibrocartilaginous tissues. 
     
     
         30 . A scaffold comprising
 a plurality of polymeric microfibers wherein each polymeric microfiber is embedded with a plurality of microspheres encapsulating at least one agent.   
     
     
         31 . The scaffold of  claim 30 , wherein each polymeric microfiber is embedded with at least a first group of microspheres and a second group of microspheres; wherein the first group of microspheres comprises a first agent and the second group of microspheres comprises a second agent different than the first agent. 
     
     
         32 . The scaffold of  claim 30 , wherein the scaffold comprises a multiphase micro-architecture and regional distribution of the first group and/or second group of microspheres. 
     
     
         33 . The scaffold of  claim 30  wherein the scaffold comprises two or more layers, each layer comprises a microfiber pattern, microfiber size or channel width that differ from the other